S922X/G12B board – BootROM alive, eMMC boot broken – low-level recovery?

    Hi everyone,

    first of all, sorry if this is slightly off-topic for the LibreELEC Amlogic section. I’m posting here because this seems to be one of the few places where people have a lot of experience with Amlogic S922X/G12B boards and their low-level boot process.

    I have a Dreambox TWO based on the S922X/G12B. After accidentally damaging the eMMC partition/boot area, the board no longer reaches U-Boot.

    The good news is that the primary BootROM is still alive. At 300 baud I get:

    G12B:BL:6e7c85:2a3b91;FEAT:F0C021B0:433060;POC:F; EMMC:0;READ:0;CHK:1F;READ:0;CHK:1F;READ:0;CHK:1F; SD?:0;SD:800;LOOP:1;

    This repeats indefinitely.

    The official Emergency SD for the device also does not get past SD:800, so at this point I’m looking for a recovery method below U-Boot level.

    My main question is whether anyone familiar with these G12B boards knows a way to force the SoC into USB BootROM mode, or whether there might be accessible eMMC ISP/test points on this board that could be used to restore the boot area.

    I have seen similar recovery procedures for other S922X/G12B devices, but I don’t want to blindly short eMMC pins or random test points on this board.

    If anyone has experience with the Dreambox ONE/TWO hardware, the Amlogic reference design behind it, or G12B low-level recovery in general, I would really appreciate any pointers.

    I’m also happy to open the device and provide detailed photos of both sides of the PCB if that would help identify possible test points.

    Thanks in advance, and again apologies if this is a little outside the usual LibreELEC topics.

    Br

    Keno

    The SoC searches for a boot firmware signature on SPI > eMMC > SD > USB but most devices don't have SPI flash so eMMC will be checked first. If you are seeing that repeating bootrom sequence either eMMC is wiped or non-functional (and the device is in its lowest level of boot mode). On a normal box that would mean easy booting from SD or USB, but Dreambox One/Two use encrypted boot firmware so you can only restore original Dreambox images that are signed with the correct keys, and most Amlogic 'factory restore' images are eMMC specific so even if you write them to USB media the device won't boot them. If there's an official SD card restore image you can see if that will also work from USB, but I suspect it won't. Normal S922X hardware is a little easier to mess with but secure boot devices are inherently more limited in options.