I contacted Andy Warne at Ultimarc, he said another user has also reported that "something has changed with the Pi 5" and recommended this fix:
sudo -E rpi-eeprom-config --edit
In the resulting config file, add:
NET_INSTALL_ENABLED=0
... and reboot. I tried it this morning and it did not fix the issue (got an uncommanded exit after about 20 minutes), but the rationale behind it made sense to me: this is the Github description of that config command, turning off that option is related to USB detection of keyboard devices:
NET_INSTALL_ENABLED
When network install is enabled, the bootloader displays the network install screen on boot if it detects a keyboard.
To enable network install, add NET_INSTALL_ENABLED=1, or to disable network install add NET_INSTALL_ENABLED=0.
This setting is ignored and network install is disabled if DISABLE_HDMI=1 is set.
In order to detect the keyboard, network install must initialise the USB controller and enumerate devices. This increases boot time by approximately 1 second so it may be advantageous to disable network install in some embedded applications.
Default: 1 on Flagship models since Raspberry Pi 4B and Keyboard models; 0 on Compute Modules since CM4 (including CM4S).
... so maybe that's worth looking into, I passed it on to Mario.
Link to Pi documentation: https://github.com/.../raspberry-pi/eeprom-bootloader.adoc
sudo -E rpi-eeprom-config --edit
In the resulting config file, add:
NET_INSTALL_ENABLED=0
... and reboot. I tried it this morning and it did not fix the issue (got an uncommanded exit after about 20 minutes), but the rationale behind it made sense to me: this is the Github description of that config command, turning off that option is related to USB detection of keyboard devices:
NET_INSTALL_ENABLED
When network install is enabled, the bootloader displays the network install screen on boot if it detects a keyboard.
To enable network install, add NET_INSTALL_ENABLED=1, or to disable network install add NET_INSTALL_ENABLED=0.
This setting is ignored and network install is disabled if DISABLE_HDMI=1 is set.
In order to detect the keyboard, network install must initialise the USB controller and enumerate devices. This increases boot time by approximately 1 second so it may be advantageous to disable network install in some embedded applications.
Default: 1 on Flagship models since Raspberry Pi 4B and Keyboard models; 0 on Compute Modules since CM4 (including CM4S).
... so maybe that's worth looking into, I passed it on to Mario.
Link to Pi documentation: https://github.com/.../raspberry-pi/eeprom-bootloader.adoc



