The information on the diagnostic screen is very helpful in getting an idea of what the bootloader is trying to do. Have you already posted a photo of this screen and I missed it? I can’t find it here.
For example at this photo:
→ SD card not inserted (this forces the diagnostic screen)
→ Message: “NVMe off”, but a few lines before it looks as if the config.txt in the boot partition was read from NVMe! And it can be seen that the kernel was the bad guy and does not provide NVMe support or is not compatible to the used bootloader.
→ additional there is version information about the current bootloader and that a power supply with max current of 5000 mA was forced via config (no USB-PD detected/negotiated).
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