Updating rpi-eeprom config in mender/yocto?

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Hi all,

So I apologies in advance for my lack of knowledge here.

We have a custom board, which if booting with raspberry os and setting VL805 to one to invoke the following behaviour

On CM4 if VL805=1 is specified in the EEPROM config then the bootloader will assume that there is a VL805 XHCI controller without a dedicated SPI EEPROM and initialise it in exactly the same manner as on Pi4B 1.4.

Via the rpi-eeprom-update our usb device(s) are recongised, however I am wondering how we’re meant to do that in yocto/mender?

Is there any other way of updating the eeprom other than using the raspberry pi tooling on the flashed image?

My assumption is the eeprom is memory on the CM4 chip itself, so not something you can typically just “flash?!”

Thanks in advance!

Alan

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Hi @Alan01252,

it sounds like it can be done: https://forums.raspberrypi.com/viewtopic.php?t=278537 but not for the faint at heart. As a first take, I’d use the tooling on the image on startup, wrapped in a small script that checks the value and eventually changes it if required.

Greets,
Josef

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Thanks @TheYoctoJester.

I did try the above, but I’m not entirely sure that’s the same problem.

The resolution in that thread is just to update the standard rpi bootloader with the appropriate customized bootloader when flashing with rpiboot.

However what we’re trying to do is use u-boot directly and so the rpi recovery bootloader isn’t used at all at this point.