Mender on pi4 with raspbian last version freeze on GPU boot sequence

General Discussions
1

We created a custom raspbian image last days using the last raspbian apt package (apt upgrade OK).
When we build the mender image from it, we face a boot problem on raspberry pi 4 (that did not occur with raspberry pi 3 and that did not occur with our golden image (before mender-convert)).

The pi 4 get stuck just after the rainbow screen with a blinking cursor.

After a long debugging sequence (using the serial UART console log), we figured out that if we replace the two following files with older versions, it makes the pi 4 boot :

  • start4.elf
  • fixup4.elf
    As we read online, these two files are related to GPU bootcode.
    Do someone know what can explain theses facts :
  • why does the mender building process affect the GPU boot sequence (as our golden image, without mender works well with both pi3 and pi4)
  • what have been changed in last GPU bootcode that can affect the boot on pi4
  • is it safe to “just” replace these two files with working one or we may face weird problem because of GPU bootcode not in sync with system files

Thanks for your help

2

Hi @Jerry

We do replace the rpi boot-files with our own custom compiled u-boot binary for rpi. However, our current setup is only 32-bit compatible.

We have been wanting to get the 64–bit support done for a while, but we are still not there unfortunately.

3

Hi @oleorhagen : our raspberry pi4 distribution is the 32 bit one. So, it seems this is not related to this issue.
Be the way : replacing the 2 files do fix the issue for us. We have tested this workaround for 2 weeks with no issue.
But i would be pleased to understand what is the underlying issue.
Regards

4

@oleorhagen is the a place where i can find the list of replaced boot-files in order to do some searching ?

5

our raspberry pi4 distribution is the 32 bit one. So, it seems this is not related to this issue.

Hmm, that is indeed unexpected then. Unless you guys are using a newer RaspiOS distribution than what we currently support ? (See the supported versions on the hub RPI page)

Alright, good :slight_smile:

I cannot be sure, I thought we didn’t replace the start.elf files.

Have a look here, in mender-convert. This is where we add u-boot as the bootloader, as the kernel so to speak, and have it again chain-load the real kernel