Boot failures when zImage size goes a little over 3MB?

Finally, back to this issue...

When I change the link address offset for booting to 0x00800000, zImage still wont load.

Also, the corresponding linux-2.6.x/vmlinux image wont load from gdb/insight nor when wrapped in a uImage for u-boot.

It's consistently hitting the BUG(mm == &init_mm); line in linux-2.6/kernel/fork.c:__mmdrop.

In this example, it's the initramfs being bigger that's preventing bootup (but turning on UBI and other kernel features causes it as well):

Will load:

vmlinux: 26028261

zImage: 3016537

System.map:__initramfs_start: 0x052919b8

System.map:_end: 0x05454575

Wont load:

vmlinux: 26115445

zImage: 3117081

System.map:__initramfs_start: 0x052919b8

System.map:_end: 0x0546cf75

Any other ideas? For PowerPC, they suggested increasing the initial memory map size. I haven't figured out the nios2 equivalent yet.