Ubuntu boot problem on rock5a using UHS class 3 micro SD

Hi all,

I initially booted Ubuntu on rock5a with 16Gb emmc, everything works fine (I had to get off the SPI flash to insert the emmc -> no initial boot with SPI flash). We then lately decided to use high speed microSD card (UHS class 3) , ubuntu doesn’t boot and display initframs console, the same rock5a boots fine using microSD class 1.

NB: Boot on UHS class 3 also works fine when I don’t initially remove the SPI flash. (all rock5a I previously booted with emmc can’t boot with microSD class3 anymore)

Could you please help how to hard reset the rock5a to reload SPI flash content?

I already tried to reset with rkdeveloptool on linux but the problem persists… :frowning: