[Bug] `fastboot boot twrp.img` doesn't boot into `blueline`'s `/dev/recovery`.

[RokeJulianLockhart]

I intended to do:

#!/usr/bin/env sh
pmbootstrap chroot fastboot reboot bootloader && \
wget https://eu.dl.twrp.me/blueline/twrp-3.7.1_12-0-blueline.img.html && \
mv twrp-3.7.1_12-0-blueline.img twrp.img && \
fastboot boot twrp.img && \
wget https://eu.dl.twrp.me/blueline/twrp-installer-3.7.1_12-0-blueline.zip.html && \
mv twrp-installer-3.7.1_12-0-blueline.zip twrp.zip && \
adb push twrp.zip

¹

However, fastboot boot, when twrp.img is appended, never actually completes:

…despite reporting to have succeeded:

RokeJulianLockhart@Beedell:~$ fastboot devices
8B5X13L84        fastboot
RokeJulianLockhart@Beedell:~$ fastboot boot twrp.img
Sending 'boot.img' (65536 KB)                      OKAY [  0.246s]
Booting                                            OKAY [  5.817s]
Finished. Total time: 6.112s

I've no UART connection, to ascertain why. adb never responds, either. Is that expected?

Tangential

For comparison, on my FP4, the undermentioned was all that I needed to do: ²

#!/usr/bin/env sh
pmbootstrap chroot fastboot reboot bootloader && \
fastboot flash recovery twrp.img && \
fastboot reboot

Is that inapplicable here? ³

Footnotes

1. gitlab.postmarketos.org/postmarketOS/pmaports/-/issues/4378 ↩

2. gitlab.postmarketos.org/postmarketOS/pmaports/-/issues/4377#note_538141 ↩

3. xdaforums.com/t/recovery-teamwin-recovery-project-blueline-official.4385769/post-90504222 ↩