Caution: I have not tested this.
IIRC the boot eeprom has support for conditional filters (excluding EDID) so it may be possible to make use of a spare GPIO and a switch to force a specific boot order.
For example:As should be obvious, the above is an addition to the current configuration (though you should probably remove any existing BOOT_ORDER= line) not a replacement for it.
I'm suggesting GPIO 2 as it has a permanent external pull up to 3.3v and (on a 4B, 400, or CM4) won't conflict with wake on GPIO 3)*. Once out of the bootloader you should be free to use the pin for other purposes. In theory any GPIO should work but you may need to add a pull up resistor to get consistent results.
Connect GPIO 2 to ground for the second BOOT_ORDER, leave it disconnected for the first.
Again, Caution: I have not tested this.
Source: https://www.raspberrypi.com/documentati ... figuration
*: earlier models don't have a boot EEPROM and the Pi 5 doesn't do wake on GPIO 3.**
**: well, mine don't.
IIRC the boot eeprom has support for conditional filters (excluding EDID) so it may be possible to make use of a spare GPIO and a switch to force a specific boot order.
For example:
Code:
[gpio2=1]BOOT_ORDER=0xf41[gpio2=0]BOOT_ORDER=0xf14[all]I'm suggesting GPIO 2 as it has a permanent external pull up to 3.3v and (on a 4B, 400, or CM4) won't conflict with wake on GPIO 3)*. Once out of the bootloader you should be free to use the pin for other purposes. In theory any GPIO should work but you may need to add a pull up resistor to get consistent results.
Connect GPIO 2 to ground for the second BOOT_ORDER, leave it disconnected for the first.
Again, Caution: I have not tested this.
Source: https://www.raspberrypi.com/documentati ... figuration
*: earlier models don't have a boot EEPROM and the Pi 5 doesn't do wake on GPIO 3.**
**: well, mine don't.
Statistics: Posted by thagrol — Thu Apr 18, 2024 10:30 pm