Inconsistent PXE boot on RPI3B

[NicoLev77]

Hi,
I'm testing one RPI3B netbooting using the PiServer tool.
The issue I'm facing is that I have to try several times to make it boot. In general, it boots ok after I turn it off like 1 hour.. When the boot success, it works great.
When the boot fails, it only shows the red led.

I've run a TCPDump and this is what happens when it fails:

11:35:08.601871 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:09.105058 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:11.108543 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:11.109269 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:13.112894 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:13.113617 IP piserver.bootps > raspberrypi.bootpc: BOOTP/DHCP, Reply, length 344
11:35:18.316476 ARP, Request who-has raspberrypi tell piserver, length 28
11:35:19.340473 ARP, Request who-has raspberrypi tell piserver, length 28
11:35:20.364482 ARP, Request who-has raspberrypi tell piserver, length 28

I've already have the last firmware and packages.
Can anyone guide me on what can be happening here?

[JamesH65]

@NicoLev77 Have you tried with the very latest bootcode etc, as I believe some changes have been made that might help?