I'm having some issues with two new Pi5s; I just wanted to boot it from USB to benchmark 3 different SD cards using the Pi as a card reader but I'm getting nowhere with the EEPROM so I tried hooking up an USB to UART adapter to have a look but I'm not getting any output other than the kernel loading if there is an SD card present in the Pi.
The factory EEPROM had:I've tried setting it to
And there is no difference, it only ever boots from the SD card and no serial output before the kernel loads. I'm not sure what to try; I wrote the 2025-10-01 Rasbperry Pi OS Lite (64-bit) to a USB drive using the Raspberry Pi Imager v1.9.6 and its not booting from USB, nor giving me any info over the serial as to why.
(I've tried giving it a server to PXE boot from as well, but also doesnt seem to work, but that might be on me and I figured I'd troubleshoot that further once I get the BOOT_UART working)
Edit: grabbed a Pi4B and verified the BOOT_UART and BOOT_ORDER works as expected with the same hardware that doesnt work with the new Pi5s. Any suggestions are welcome!
The factory EEPROM had:
Code:
BOOT_UART=1BOOT_ORDER=0xf461NET_INSTALL_AT_POWER_ON=1Code:
BOOT_UART=1BOOT_ORDER=0x24NET_INSTALL_AT_POWER_ON=0(I've tried giving it a server to PXE boot from as well, but also doesnt seem to work, but that might be on me and I figured I'd troubleshoot that further once I get the BOOT_UART working)
Edit: grabbed a Pi4B and verified the BOOT_UART and BOOT_ORDER works as expected with the same hardware that doesnt work with the new Pi5s. Any suggestions are welcome!
Statistics: Posted by bearer — Sat Nov 08, 2025 10:15 pm — Replies 3 — Views 84