diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f4d7f3de5..519f82ffd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -51,3 +51,5 @@ jobs:
         run: pushd examples; ./build_all.sh || exit; popd
       - name: ci-debug-build
         run: pushd examples/blink; make debug RAM_START=0x20004000 FLASH_INIT=0x30051 || exit; popd
+      - name: ci-build-picolib
+        run: pushd examples/tests/hello_loop; make clean; make PICOLIB=1 || exit; popd
diff --git a/Configuration.mk b/Configuration.mk
index f7408f70e..a0709f1ea 100644
--- a/Configuration.mk
+++ b/Configuration.mk
@@ -197,6 +197,12 @@ override CPPFLAGS_PIC += \
       -Wl,--emit-relocs\
       -fPIC
 
+ifneq ($(PICOLIB),)
+  # Use picolib for libc. We need to include the `picolib-tock` library which
+  # maps Tock's system-level functions to the names that picolib expects.
+  EXTERN_LIBS += $(TOCK_USERLAND_BASE_DIR)/picolib-tock
+endif
+
 ################################################################################
 ##
 ## RISC-V compiler/linker flags
@@ -256,10 +262,19 @@ else ifeq ($(CC_rv32_version_major),13)
 else
   NEWLIB_VERSION_rv32 := 4.3.0.20230120
 endif
-NEWLIB_VERSION_rv32i    := $(NEWLIB_VERSION_rv32)
-NEWLIB_VERSION_rv32imc  := $(NEWLIB_VERSION_rv32)
-NEWLIB_VERSION_rv32imac := $(NEWLIB_VERSION_rv32)
-NEWLIB_BASE_DIR_rv32 := $(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-$(NEWLIB_VERSION_rv32)
+
+ifeq ($(PICOLIB),)
+  # Use newlib
+  TOCK_LIBC_FOLDER_rv32 := libtock-newlib-$(NEWLIB_VERSION_rv32)
+else
+  # Use picolib
+  TOCK_LIBC_FOLDER_rv32 := libtock-picolib-1.8.5
+endif
+
+TOCK_LIBC_FOLDER_rv32i    := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_FOLDER_rv32imc  := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_FOLDER_rv32imac := $(TOCK_LIBC_FOLDER_rv32)
+TOCK_LIBC_BASE_DIR_rv32   := $(TOCK_USERLAND_BASE_DIR)/lib/$(TOCK_LIBC_FOLDER_rv32)
 
 # Match compiler version to supported libtock-libc++ versions.
 ifeq ($(CC_rv32_version_major),10)
@@ -299,7 +314,7 @@ override CFLAGS_rv32imac += $(CFLAGS_rv32)
 # Set the base `CPPFLAGS` for all RISC-V variants based on the toolchain family.
 override CPPFLAGS_rv32 += \
       $(CPPFLAGS_toolchain_rv32) \
-      -isystem $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include \
+      -isystem $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include \
       -isystem $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include/c++/$(LIBCPP_VERSION_rv32) \
       -isystem $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/include/c++/$(LIBCPP_VERSION_rv32)/riscv64-unknown-elf
 
@@ -330,8 +345,8 @@ override WLFLAGS_rv32imc  += $(WLFLAGS_rv32)
 override WLFLAGS_rv32imac += $(WLFLAGS_rv32)
 
 override SYSTEM_LIBS_rv32i    += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32i += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32i/ilp32/libstdc++.a \
@@ -339,8 +354,8 @@ override SYSTEM_LIBS_CXX_rv32i += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/lib/gcc/riscv64-unknown-elf/$(LIBCPP_VERSION_rv32)/rv32i/ilp32/libgcc.a
 
 override SYSTEM_LIBS_rv32imc  += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32imc += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32im/ilp32/libstdc++.a \
@@ -348,8 +363,8 @@ override SYSTEM_LIBS_CXX_rv32imc += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/lib/gcc/riscv64-unknown-elf/$(LIBCPP_VERSION_rv32)/rv32im/ilp32/libgcc.a
 
 override SYSTEM_LIBS_rv32imac += \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libc.a \
-      $(NEWLIB_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libm.a
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libc.a \
+      $(TOCK_LIBC_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libm.a
 
 override SYSTEM_LIBS_CXX_rv32imac += \
       $(LIBCPP_BASE_DIR_rv32)/riscv/riscv64-unknown-elf/lib/rv32imac/ilp32/libstdc++.a \
@@ -396,11 +411,20 @@ else ifeq ($(CC_cortex-m_version_major),13)
 else
   NEWLIB_VERSION_cortex-m := 4.3.0.20230120
 endif
-NEWLIB_VERSION_cortex-m0 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m3 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m4 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_VERSION_cortex-m7 := $(NEWLIB_VERSION_cortex-m)
-NEWLIB_BASE_DIR_cortex-m := $(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-$(NEWLIB_VERSION_cortex-m)
+
+ifeq ($(PICOLIB),)
+  # Use newlib
+  TOCK_LIBC_FOLDER_cortex-m := libtock-newlib-$(NEWLIB_VERSION_cortex-m)
+else
+  # Use picolib
+  TOCK_LIBC_FOLDER_cortex-m := libtock-picolib-1.8.5
+endif
+
+TOCK_LIBC_FOLDER_cortex-m0  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m3  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m4  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_FOLDER_cortex-m7  := $(TOCK_LIBC_FOLDER_cortex-m)
+TOCK_LIBC_BASE_DIR_cortex-m := $(TOCK_USERLAND_BASE_DIR)/lib/$(TOCK_LIBC_FOLDER_cortex-m)
 
 # Match compiler version to supported libtock-libc++ versions.
 ifeq ($(CC_cortex-m_version_major),10)
@@ -441,7 +465,7 @@ override CPPFLAGS_cortex-m += \
       -msingle-pic-base\
       -mpic-register=r9\
       -mno-pic-data-is-text-relative\
-      -isystem $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/include\
+      -isystem $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/include\
       -isystem $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/include/c++/$(LIBCPP_VERSION_cortex-m)\
       -isystem $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/include/c++/$(LIBCPP_VERSION_cortex-m)/arm-none-eabi
 
@@ -460,8 +484,8 @@ override CPPFLAGS_cortex-m7 += $(CPPFLAGS_cortex-m) \
       -mcpu=cortex-m7
 
 override SYSTEM_LIBS_cortex-m0 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m0 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v6-m/nofp/libstdc++.a \
@@ -469,8 +493,8 @@ override SYSTEM_LIBS_CXX_cortex-m0 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v6-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m3 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m3 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7-m/nofp/libstdc++.a \
@@ -478,8 +502,8 @@ override SYSTEM_LIBS_CXX_cortex-m3 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v7-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m4 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m4 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libstdc++.a \
@@ -487,8 +511,8 @@ override SYSTEM_LIBS_CXX_cortex-m4 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/lib/gcc/arm-none-eabi/$(LIBCPP_VERSION_cortex-m)/thumb/v7e-m/nofp/libgcc.a
 
 override SYSTEM_LIBS_cortex-m7 += \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
-      $(NEWLIB_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libc.a \
+      $(TOCK_LIBC_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libm.a
 
 override SYSTEM_LIBS_CXX_cortex-m7 += \
       $(LIBCPP_BASE_DIR_cortex-m)/arm/arm-none-eabi/lib/thumb/v7e-m/nofp/libstdc++.a \
diff --git a/Precompiled.mk b/Precompiled.mk
index 9545c06bc..757118a6d 100644
--- a/Precompiled.mk
+++ b/Precompiled.mk
@@ -44,8 +44,8 @@ RISCV_ARCHS := rv32i/ilp32 rv32im/ilp32 rv32imac/ilp32
 # - $(3): Arch
 define PRECOMPILED_NEWLIB_RULES
 
-TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libc.a
-TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libm.a
+TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-%/$(1)/$(2)/lib/$(3)/libc.a
+TOCK_NEWLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-newlib-%/$(1)/$(2)/lib/$(3)/libm.a
 
 endef
 
@@ -55,10 +55,45 @@ $(foreach arch,$(RISCV_ARCHS),$(eval $(call PRECOMPILED_NEWLIB_RULES,riscv,riscv
 
 # Target to download and extract newlib.
 #
-# % will match something like "libtock-newlib-4.2.0.20211231" which we then
-# strip down to just the version with some string manipulation.
+# `$*` will match the version number in the libtock-newlib folder name
+# (something like "libtock-newlib-4.2.0.20211231").
 $(TOCK_NEWLIB_TARGETS):
-	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-newlib.sh $(patsubst libtock-newlib-%,%,$*)
+	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-newlib.sh $*
+
+################################################################################
+# Picolib Rules
+#
+# These pre-compiled archives were created using the libtock-c/picolib folder.
+################################################################################
+
+# Rule to ensure that the picolib libraries for an architecture exist.
+#
+# Need to list all libraries which are possible targets into one variable. It is
+# imperative that the wildcard `%` expands to the same value for every target to
+# tell make that one invocation of this build rule will make all the target
+# files.
+#
+# Arguments:
+# - $(1): Family
+# - $(2): Toolchain
+# - $(3): Arch
+define PRECOMPILED_PICOLIB_RULES
+
+TOCK_PICOLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-picolib-%/$(1)/$(2)/lib/$(3)/libc.a
+TOCK_PICOLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/libtock-picolib-%/$(1)/$(2)/lib/$(3)/libm.a
+
+endef
+
+TOCK_PICOLIB_TARGETS :=
+$(foreach arch,$(ARM_ARCHS),$(eval $(call PRECOMPILED_PICOLIB_RULES,arm,arm-none-eabi,$(arch))))
+$(foreach arch,$(RISCV_ARCHS),$(eval $(call PRECOMPILED_PICOLIB_RULES,riscv,riscv64-unknown-elf,$(arch))))
+
+# Target to download and extract picolib.
+#
+# `$*` will match the version number in the libtock-picolib folder name
+# (something like "libtock-picolib-1.8.5").
+$(TOCK_PICOLIB_TARGETS):
+	cd $(TOCK_USERLAND_BASE_DIR)/lib; ./fetch-picolib.sh $*
 
 ################################################################################
 # LIBC++ Rules
@@ -75,7 +110,7 @@ TOCK_CXXLIB_TARGETS += $$(TOCK_USERLAND_BASE_DIR)/lib/%/$(1)/$(2)/lib/$(3)/libsu
 # So this is supremely frustrating. The issue boils down to limitations of
 # pattern rules in make.
 #
-# First: pattern rules are implicitly groups, and you aren't allowed to 
+# First: pattern rules are implicitly groups, and you aren't allowed to
 # use the :g operator to merge groups. What this means in practice is that
 # if you have many targets that are all generated by the same rule (i.e.,
 # our unzip creates all the library archive targets), all of the targets
diff --git a/lib/fetch-picolib.sh b/lib/fetch-picolib.sh
new file mode 100755
index 000000000..38f75f7bf
--- /dev/null
+++ b/lib/fetch-picolib.sh
@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+
+PICOLIB_VERSION=$1
+
+if [ $PICOLIB_VERSION = "1.8.5" ]; then
+  PICOLIB_SHA="5168a7ea6522717ec5867e0105a224fe7e3779371b095deedc2cd58da369d8cc"
+fi
+
+# Name of the pre-created compiled directories.
+ZIP_FILE=libtock-picolib-$PICOLIB_VERSION.zip
+
+# List of mirrors we support.
+MIRRORS=(\
+  "https://www.cs.virginia.edu/~bjc8c/archive/tock"\
+  "https://alpha.mirror.svc.schuermann.io/files"\
+)
+
+let FOUND=0
+
+# Try from each mirror until we successfully download a .zip file.
+for MIRROR in ${MIRRORS[@]}; do
+  URL=$MIRROR/$ZIP_FILE
+  echo "Fetching picolib from ${MIRROR}..."
+  echo "  Fetching ${URL}..."
+  wget -q "$URL" && (echo "$PICOLIB_SHA $ZIP_FILE" | sha256sum -c)
+  if [ $? -ne 0 ]; then
+    echo "  WARNING: Fetching picolib from mirror $MIRROR failed!" >&2
+  else
+    let FOUND=1
+    break
+  fi
+done
+
+if [[ $FOUND -ne 0 ]]; then
+  unzip $ZIP_FILE
+else
+  echo "ERROR: Unable to find tock-picolib"
+  exit -1
+fi
diff --git a/libtock-sync/sys.c b/libtock-sync/sys.c
index a26a1cafd..d1921bb06 100644
--- a/libtock-sync/sys.c
+++ b/libtock-sync/sys.c
@@ -1,5 +1,7 @@
 #include "interface/console.h"
 
+#include "tock_sys.h"
+
 // XXX Suppress missing prototype warnings for this file as the headers should
 // be in newlib internals, but first stab at including things didn't quite work
 // and the warnings are just noise
@@ -11,8 +13,6 @@
 // SYNCHRONOUS LIBC SUPPORT STUBS
 // ------------------------------
 
-int _write(__attribute__ ((unused)) int fd, const void* buf, uint32_t count) {
-  int written;
-  libtocksync_console_write((const uint8_t*) buf, count, &written);
-  return written;
+int _write(int fd, const void* buf, uint32_t count) {
+  return _tock_write(fd, buf, count);
 }
diff --git a/libtock-sync/tock_sys.c b/libtock-sync/tock_sys.c
new file mode 100644
index 000000000..be5df3644
--- /dev/null
+++ b/libtock-sync/tock_sys.c
@@ -0,0 +1,18 @@
+#include "interface/console.h"
+
+// XXX Suppress missing prototype warnings for this file as the headers should
+// be in newlib internals, but first stab at including things didn't quite work
+// and the warnings are just noise
+#pragma GCC diagnostic ignored "-Wmissing-declarations"
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+
+// ------------------------------
+// SYNCHRONOUS LIBC SUPPORT STUBS
+// ------------------------------
+
+int _tock_write(__attribute__ ((unused)) int fd, const void* buf, uint32_t count) {
+  int written;
+  libtocksync_console_write((const uint8_t*) buf, count, &written);
+  return written;
+}
diff --git a/libtock-sync/tock_sys.h b/libtock-sync/tock_sys.h
new file mode 100644
index 000000000..bd5fb624d
--- /dev/null
+++ b/libtock-sync/tock_sys.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int _tock_write(int fd, const void* buf, uint32_t count);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/libtock/sys.c b/libtock/sys.c
index 0a81e819c..7d334788f 100644
--- a/libtock/sys.c
+++ b/libtock/sys.c
@@ -4,6 +4,7 @@
 
 #include "interface/console.h"
 #include "tock.h"
+#include "tock_sys.h"
 
 // XXX Suppress unused parameter warnings for this file as the implementations
 // are currently all just stubs
@@ -28,29 +29,9 @@ void* __dso_handle = 0;
 int _unlink(const char* pathname) {
   return -1;
 }
-
-int _isatty(int fd) {
-  if (fd == 0) {
-    return 1;
-  }
-  return 0;
-}
 int _open(const char* path, int flags, ...) {
   return -1;
 }
-int _close(int fd) {
-  return -1;
-}
-int _fstat(int fd, struct stat* st) {
-  st->st_mode = S_IFCHR;
-  return 0;
-}
-int _lseek(int fd, uint32_t offset, int whence) {
-  return 0;
-}
-int _read(int fd, void* buf, uint32_t count) {
-  return 0;   // k_read(fd, (uint8_t*) buf, count);
-}
 void _exit(int __status) {
   tock_exit((uint32_t) __status);
 }
@@ -61,12 +42,22 @@ int _kill(pid_t pid, int sig) {
   return -1;
 }
 
+// FOR NEWLIB
+int _fstat(int fd, struct stat* st) {
+  return _tock_fstat(fd, st);
+}
+int _isatty(int fd) {
+  return _tock_isatty(fd);
+}
+int _read(int fd, void* buf, uint32_t count) {
+  return _tock_read(fd, buf, count);
+}
+int _lseek(int fd, uint32_t offset, int whence) {
+  return _tock_lseek(fd, offset, whence);
+}
+int _close(int fd) {
+  return _tock_close(fd);
+}
 caddr_t _sbrk(int incr) {
-  memop_return_t ret;
-  ret = memop(1, incr);
-  if (ret.status != TOCK_STATUSCODE_SUCCESS) {
-    errno = ENOMEM;
-    return (caddr_t) -1;
-  }
-  return (caddr_t) ret.data;
+  return _tock_sbrk(incr);
 }
diff --git a/libtock/tock_sys.c b/libtock/tock_sys.c
new file mode 100644
index 000000000..0dabd8966
--- /dev/null
+++ b/libtock/tock_sys.c
@@ -0,0 +1,50 @@
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "tock.h"
+
+// XXX Suppress unused parameter warnings for this file as the implementations
+// are currently all just stubs
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+
+// XXX Suppress missing prototype warnings for this file as the headers should
+// be in newlib internals, but first stab at including things didn't quite work
+// and the warnings are just noise
+#pragma GCC diagnostic ignored "-Wmissing-declarations"
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+
+int _tock_close(int fd) {
+  return -1;
+}
+
+int _tock_lseek(int fd, uint32_t offset, int whence) {
+  return 0;
+}
+
+int _tock_read(int fd, void* buf, uint32_t count) {
+  return 0;
+}
+
+int _tock_isatty(int fd) {
+  if (fd == 0) {
+    return 1;
+  }
+  return 0;
+}
+
+int _tock_fstat(int fd, struct stat* st) {
+  st->st_mode = S_IFCHR;
+  return 0;
+}
+
+caddr_t _tock_sbrk(int incr) {
+  memop_return_t ret;
+  ret = memop(1, incr);
+  if (ret.status != TOCK_STATUSCODE_SUCCESS) {
+    errno = ENOMEM;
+    return (caddr_t) -1;
+  }
+  return (caddr_t) ret.data;
+}
diff --git a/libtock/tock_sys.h b/libtock/tock_sys.h
new file mode 100644
index 000000000..1b5ccdfce
--- /dev/null
+++ b/libtock/tock_sys.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "tock.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int _tock_close(int fd);
+int _tock_lseek(int fd, uint32_t offset, int whence);
+int _tock_read(int fd, void* buf, uint32_t count);
+int _tock_isatty(int fd);
+int _tock_fstat(int fd, struct stat* st);
+caddr_t _tock_sbrk(int incr);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/picolib-tock/Makefile b/picolib-tock/Makefile
new file mode 100644
index 000000000..e86c76ada
--- /dev/null
+++ b/picolib-tock/Makefile
@@ -0,0 +1,11 @@
+# Base folder definitions
+TOCK_USERLAND_BASE_DIR ?= ..
+LIBNAME := picolib-tock
+$(LIBNAME)_DIR := $(TOCK_USERLAND_BASE_DIR)/$(LIBNAME)
+
+# List all C and Assembly files
+$(LIBNAME)_SRCS  := $(wildcard $($(LIBNAME)_DIR)/*.c)
+
+override CPPFLAGS_$(LIBNAME) += -I$(TOCK_USERLAND_BASE_DIR)/libtock
+
+include $(TOCK_USERLAND_BASE_DIR)/TockLibrary.mk
diff --git a/picolib-tock/README.md b/picolib-tock/README.md
new file mode 100644
index 000000000..7afa5180a
--- /dev/null
+++ b/picolib-tock/README.md
@@ -0,0 +1,19 @@
+Picolib - Tock Library
+======================
+
+This library provides helper functions to connect picolib system functions to
+Tock-provided functions.
+
+Specifically, picolib expects these functions:
+
+- `int fstat(int fd, struct stat *st)`
+- `int isatty(int fd)`
+- `int read(int fd, void *buf, uint32_t count)`
+- `int write(int fd, const void *buf, uint32_t count)`
+- `int lseek(int fd, uint32_t offset, int whence)`
+- `int close(int fd)`
+- `caddr_t sbrk(int incr)`
+
+These names are different from what newlib expects. Since the underscore
+versions are less likely to conflict, we include those functions in libtock
+directly, and then only include this library when picolib is being used.
diff --git a/picolib-tock/picolib-tock.c b/picolib-tock/picolib-tock.c
new file mode 100644
index 000000000..80da51ecc
--- /dev/null
+++ b/picolib-tock/picolib-tock.c
@@ -0,0 +1,39 @@
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <libtock-sync/tock_sys.h>
+#include <libtock/tock.h>
+#include <libtock/tock_sys.h>
+
+// Suppress missing prototype warnings for this file as the headers should be in
+// picolib internals.
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+
+int __errno_global;
+int* __errno(void) {
+  return &__errno_global;
+}
+
+// FOR PICOLIB
+int fstat(int fd, struct stat* st) {
+  return _tock_fstat(fd, st);
+}
+int isatty(int fd) {
+  return _tock_isatty(fd);
+}
+int read(int fd, void* buf, uint32_t count) {
+  return _tock_read(fd, buf, count);
+}
+int write(int fd, const void* buf, uint32_t count) {
+  return _tock_write(fd, buf, count);
+}
+int lseek(int fd, uint32_t offset, int whence) {
+  return _tock_lseek(fd, offset, whence);
+}
+int close(int fd) {
+  return _tock_close(fd);
+}
+caddr_t sbrk(int incr) {
+  return _tock_sbrk(incr);
+}
diff --git a/picolib/.gitignore b/picolib/.gitignore
new file mode 100644
index 000000000..855b824ba
--- /dev/null
+++ b/picolib/.gitignore
@@ -0,0 +1,3 @@
+libtock-picolib*
+picolib-*
+picolibc-*
diff --git a/picolib/Makefile b/picolib/Makefile
new file mode 100644
index 000000000..5291b7584
--- /dev/null
+++ b/picolib/Makefile
@@ -0,0 +1,49 @@
+all: rebuild-picolib
+
+ifeq ($(PICOLIB_VERSION),)
+  $(error Need to set the PICOLIB_VERSION variable to choose which to build.)
+endif
+
+picolib-$(PICOLIB_VERSION).tar.xz:
+	@echo "Downloading picolib source $(@F)"
+	@wget -q -O $@ https://github.com/picolibc/picolibc/releases/download/$(PICOLIB_VERSION)/picolibc-$(PICOLIB_VERSION).tar.xz
+
+picolibc-$(PICOLIB_VERSION): picolib-$(PICOLIB_VERSION).tar.xz
+	@echo "Extracting $(<F)"
+	@tar -xzf $<
+	@touch $@ # Touch so directory appears newer than tarball
+
+rebuild-picolib: picolibc-$(PICOLIB_VERSION)
+	@rm -rf picolib-arm-$(PICOLIB_VERSION)-out
+	@rm -rf picolib-arm-$(PICOLIB_VERSION)-install
+	@rm -rf picolib-riscv-$(PICOLIB_VERSION)-out
+	@rm -rf picolib-riscv-$(PICOLIB_VERSION)-install
+	@rm -rf libtock-picolib-$(PICOLIB_VERSION).zip
+	@rm -rf libtock-picolib-$(PICOLIB_VERSION)
+	@echo ""
+	@echo "=== BEGINNING ARM BUILD =========================="
+	@echo ""
+	@mkdir -p picolib-arm-$(PICOLIB_VERSION)-out
+	@mkdir -p picolib-arm-$(PICOLIB_VERSION)-install
+	@echo "Entering directory picolib-arm-$(PICOLIB_VERSION)-out"
+	cd picolib-arm-$(PICOLIB_VERSION)-out; ../build-arm.sh ../$< ../picolib-arm-$(PICOLIB_VERSION)-install | tee build-arm.log
+	@echo ""
+	@echo "=== BEGINNING RISC-V BUILD ======================="
+	@echo ""
+	@mkdir -p picolib-riscv-$(PICOLIB_VERSION)-out
+	@mkdir -p picolib-riscv-$(PICOLIB_VERSION)-install
+	@echo "Entering directory picolib-riscv-$(PICOLIB_VERSION)-out"
+	cd picolib-riscv-$(PICOLIB_VERSION)-out; ../build-riscv.sh ../$< ../picolib-riscv-$(PICOLIB_VERSION)-install | tee build-riscv.log
+	@echo ""
+	@echo "=== PACKAGING PICOLIB ARTIFACTS ==================="
+	@echo ""
+	@mkdir -p libtock-picolib-$(PICOLIB_VERSION)/arm
+	@mkdir -p libtock-picolib-$(PICOLIB_VERSION)/riscv
+	@cp -r picolib-arm-$(PICOLIB_VERSION)-install/picolibc/arm-none-eabi libtock-picolib-$(PICOLIB_VERSION)/arm
+	@cp -r picolib-riscv-$(PICOLIB_VERSION)-install/picolibc/riscv64-unknown-elf libtock-picolib-$(PICOLIB_VERSION)/riscv
+	@mv picolib-arm-$(PICOLIB_VERSION)-out/build-arm.log picolib-riscv-$(PICOLIB_VERSION)-out/build-riscv.log libtock-picolib-$(PICOLIB_VERSION)
+	@zip -r libtock-picolib-$(PICOLIB_VERSION).zip libtock-picolib-$(PICOLIB_VERSION)
+	@echo ""
+	@echo "=== FINISHED PICOLIB ZIP =========================="
+	@echo ""
+	@sha256sum libtock-picolib-$(PICOLIB_VERSION).zip
diff --git a/picolib/README.md b/picolib/README.md
new file mode 100644
index 000000000..24d97410d
--- /dev/null
+++ b/picolib/README.md
@@ -0,0 +1,38 @@
+Tock Userland libc  - Picolibc
+==============================
+
+[Picolibc](https://github.com/picolibc/picolibc) is a port of the C standard
+library designed for embedded systems. Tock uses a version of Picolibc compiled
+to support the position independent code that Tock applications require.
+
+Compiling a new version of Picolibc
+-----------------------------------
+
+This folder contains scripts to build and package picolibc for libtock-c.
+
+### Simple Directions
+
+If you want to build and package picolibc locally you can use the provided
+`Makefile`.
+
+You must choose by setting the variable `PICOLIB_VERSION` with the version you
+want to compile. The releases are listed
+[here](https://github.com/picolibc/picolibc/releases).
+
+Then:
+
+    $ make PICOLIB_VERSION=1.8.5
+
+When the build finishes (it takes a while), a zip folder named
+`libtock-picolib-<version>.zip` will contain the built libraries. You can move
+that folder to the `libtock-c/lib` directory to use the new version of newlib.
+
+### Docker
+
+To help with reproducibility, we provide Dockerfiles for various versions of
+newlib that can generate the compiled version of libtock-picolib.
+
+```bash
+cd docker/docker-picolib-<version>
+./docker-create.sh
+```
diff --git a/picolib/build-arm.sh b/picolib/build-arm.sh
new file mode 100755
index 000000000..d55ac68e2
--- /dev/null
+++ b/picolib/build-arm.sh
@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+set -x
+
+PICOLIB_SRC_DIR=$1
+PICOLIB_INSTALL_DIR=$2
+
+# We want to end up with newlib compiled for at least the `v6-m/nofp`,
+# `v7-m/nofp`, and `v7e-m/nofp` architectures. For that to happen the
+# arm-none-eabi-gcc compiler must have been compiled with multilib support for
+# those architectures. We verify that here before actually building anything.
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v6-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v6-m/nofp"
+  exit -1
+fi
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v7-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v7-m/nofp"
+  exit -1
+fi
+if ! arm-none-eabi-gcc --print-multi-lib | grep -q 'v7e-m/nofp'; then
+  echo "ERROR: arm-none-eabi-gcc not configured with multilib support for v7e-m/nofp"
+  exit -1
+fi
+
+# Picolibc Configure Flags
+#
+# picolib=false             # Do not use picolib sbrk. We need to use the memop syscalls.
+# picocrt=false             # Do not build crt0, we have our own.
+# picocrt-lib=false         # Do not package crt0.
+# tinystdio=false           # Do not use AVR tinystdio, which uses a different underlying interface (aka stdout object).
+# newlib-stdio64=false      # Do not include 64 bit APIs.
+# newlib-reent-small=true   # Disable reentrancy support to save space
+# newlib-global-atexit=true # Disable reentrancy for `atexit` (saves space)
+$PICOLIB_SRC_DIR/scripts/do-configure arm-none-eabi -Dprefix=`realpath $PICOLIB_INSTALL_DIR` \
+  -Dpicolib=false \
+  -Dpicocrt=false \
+  -Dpicocrt-lib=false \
+  -Dtinystdio=false \
+  -Dnewlib-stdio64=false \
+  -Dnewlib-reent-small=true \
+  -Dnewlib-global-atexit=true \
+  -Dmultilib-list=thumb/v6-m/nofp,thumb/v7-m/nofp,thumb/v7e-m/nofp \
+  -Dc_args="-g -Os -ffunction-sections -fdata-sections -fPIC -msingle-pic-base -mno-pic-data-is-text-relative"
+
+ninja
+ninja install
diff --git a/picolib/build-riscv.sh b/picolib/build-riscv.sh
new file mode 100755
index 000000000..fe51421c6
--- /dev/null
+++ b/picolib/build-riscv.sh
@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -x
+
+PICOLIB_SRC_DIR=$1
+PICOLIB_INSTALL_DIR=$2
+
+$PICOLIB_SRC_DIR/scripts/do-configure riscv64-unknown-elf -Dprefix=`realpath $PICOLIB_INSTALL_DIR` \
+  -Dpicolib=false \
+  -Dpicocrt=false \
+  -Dpicocrt-lib=false \
+  -Dtinystdio=false \
+  -Dnewlib-stdio64=false \
+  -Dmultilib-list=rv32i/ilp32,rv32im/ilp32,rv32imac/ilp32 \
+  -Dnewlib-reent-small=true \
+  -Dnewlib-global-atexit=true
+
+ninja
+ninja install
diff --git a/picolib/docker/docker-picolib-1.8.5/Dockerfile b/picolib/docker/docker-picolib-1.8.5/Dockerfile
new file mode 100644
index 000000000..b83c1ae16
--- /dev/null
+++ b/picolib/docker/docker-picolib-1.8.5/Dockerfile
@@ -0,0 +1,28 @@
+###
+### Dockerfile to build libtock-picolib-1.8.5
+###
+
+# We get version 12 of arm-none-eabi-gcc/riscv64-unknown-elf-gcc.
+FROM debian:bookworm
+
+LABEL maintainer="Tock Project Developers <tock-dev@googlegroups.com>"
+LABEL version="0.1"
+LABEL description="Dockerfile to build libtock-c picolib 1.8.5."
+
+# Disable Prompt During Packages Installation
+ARG DEBIAN_FRONTEND=noninteractive
+# Update Ubuntu Software repository
+RUN apt update
+
+# Install our toolchains
+RUN apt install -y gcc-arm-none-eabi gcc-riscv64-unknown-elf
+
+# Install needed tools
+RUN apt install -y git build-essential ninja-build meson zip
+
+# Clone the libtock-c source so we can use the build scripts
+RUN git clone https://github.com/tock/libtock-c -b make-precompiled-picolib
+RUN cd libtock-c && git fetch && git checkout 6dc8907938e7daa307650ba6577a59c25214ef3f
+
+# Actually build the toolchain
+RUN cd libtock-c/picolib && make PICOLIB_VERSION=1.8.5
diff --git a/picolib/docker/docker-picolib-1.8.5/docker-create.sh b/picolib/docker/docker-picolib-1.8.5/docker-create.sh
new file mode 100755
index 000000000..71fb33f0c
--- /dev/null
+++ b/picolib/docker/docker-picolib-1.8.5/docker-create.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+docker build -t libtock-c-picolib-1.8.5 .
+id=$(docker create libtock-c-picolib-1.8.5)
+docker cp $id:/libtock-c/newlib/libtock-picolib-1.8.5.zip libtock-picolib-1.8.5.zip