While true. My setup was the following: I was using the mainboard 2.5 with the the first SOM and was booting from SD card which came with the Reform. Transcend 32 GB. Without any problems. I installed the mainboard 3.0 and RK3588 and I could not read the SD card anymore. With an external SD card reader I was able to get to read the SD card without any problems.
So I’ve finally got to try different SD cards. Well, every card I tried worked exept Transend 32 GB which came with the Reform2 and I was able to read with an USB SD card reader. At this point I would say my MB 3.0 is not broken. But I still can’t understand why I was able to work from this SD card with the original MB and with the MB2.5 for so long and even boot from it and with MB3.0 I can’t.