I have a custom-designed PCB using the i.MX233 based on the Olinuxino and the EVK. When I boot U-Boot/Linux 3.12 off a microSD card, the board reboots sporadically while starting. It sometimes makes it as far as "Starting kernel ... " but often doesn't get past "Flattening Device Tree blob".
Should I be investigating power supply issues? I have 47 uF and 100 nF ceramics on the DC/DC converter pins, plus 4.7 uF + 100 nF ceramics on the linear regular pins, and 100 nF caps on all the supply pins.
Or could it be DDR memory issues? The first lane of the x16 DDR is matched to 1100±100 mil. The second lane is matched to 600±100 mil. The address lines aren't length-matched, and vary between about 400 and 900 mil.
I'd like to try lowering the DDR memory speed to see if that resolves the issue, but I'm not sure where that value is located in the source code. I have an up-to-date Yocto environment.
Any help would be greatly appreciated! Thanks!