We had a previous ticket for bumping the RaspiOS image https://tracker.mender.io/browse/MEN-4395, which we thought was fixed with the U-Boot bump to version `2020.01`. Turns out that this fix only works when the uart is enabled during boot.
The culprit is still unknown, but the working theory is that it has to do with the RaspiOS firmware, more explicitly `start.elf` (start4.elf for RPi4), and how it interracts with U-Boot when uart is not enabled. When UART is enabled, the GPU clock (The GPU runs the start.elf binary file as the 2nd stage bootloader), is set to a fixed frequency, since this clock is divided for use with the UART during boot.
For more information, have a look at this Mender-Hub post: https://hub.mender.io/t/raspios-versions-vs-mender-convert-versions/3398/9?u=oleorhagen
- Make mender-convert work the newer RaspiOS image
- Make sure it works both with and without UART enabled (this is what burnt us last time)
|2020.01||only with UART enabled|