Booting barebox on i.MX6 from SDCARD?

[Holger Schurig]

Hmm, this is really weird.

On my device, I have a WinCE image on a MMC card. When I insert this
MMC card, the hardware boots from it and I see the output of the EBOOT
on the serial port. So I know that the hardware can boot from SDCARD
(e.g. BOOTCFG setup etc). If I remove the card, then the CPU instead
activates serial (USB) boot, as I can see with lsusb/journalctl -f.

Now I use the exact same MMC card and put
barebox/images/barebox-ahs2.img onto it. This is an image that I can
boot via "barebox/scripts/imx/imx-usb-loader -v
barebox/images/barebox-ahs2.img". So I know that this image isn't
totally borked up ...  As I insert this card now and turn the power on
....   nothing happens. The hardware seems dead, even with
CONFIG_DEBUG_LL.

Doesn't seem to matter if I put the image onto the MMC card with or
without bs=512 skip=1 seek=1.

(I also used SDCARD in a Sandisk MMC->SDCARD adapter. But beware: my
sandisk adapter doesn't provide a proper card detect signal ...)