The initrd (ramdisk) contents are in flash at 0b0000, and are reprogrammed by any s/w upgrade. I'm not sure what the initrd is used for, since the linuxrc executable therein is a binary (rather than the usual simple command script).

But regardless -- your memory is bad. The Hijack DRAM test is not exhaustive, nor failsafe, since achieving those goals would significantly slow down boot times. But odds are very good that the data pins are fine, and the problem you have is with the address lines. Touch all of those up with the iron and try again.

Cheers