What jumps out at you between those two SA? I think it could be a factor that JB is formatting all of /system whereas ICS rom does not.
Well, I suspect what you're going to say:
ICS snippet:
format("ext4", "EMMC", "/dev/block/platform/omap/omap_hsmmc.0/by-name/system", "0");
mount("ext4", "EMMC", "/dev/block/platform/omap/omap_hsmmc.0/by-name/system", "/system");
vs.
JB snippet:
format("ext4", "EMMC", "/dev/block/platform/omap/omap_hsmmc.0/by-name/system", "0", "/system");
mount("ext4", "EMMC", "/dev/block/platform/omap/omap_hsmmc.0/by-name/system", "/system");
is the difference in the JB format command, right?
edit: you ninja'd an edit on me while I was looking at the pastebins
.

