What is inside of the 4 partitions of Kindle DX(g)?

I seem to have broken something and my Kindle DX no longer boots due to not finding an init system. I tried to mount the mmc over usb and fix it that way but it appears that the partition formats are wiped. I was able to binwalk over the p1 and found remnants of the files but it's pretty fragmented with the -e parameter.

mmcblk0 p1 - 400M
p2 - 24M
p3 - 8M
p4 - 3.XG (I know what this is)

Any ideas where to go from here?
I have serial access.