failing to boot from mfsroot.gz

[Richard P. Williamson]

Hello all,

I have a 4.8 system that booted from flash using a kernel.gz and mfsroot.gz.
The ethernet parts were not fully supported by the fxp driver in 4.8,
so I was testing 4.10 to see if they were with that version of the OS.

I've replace the kernel.gz with a 4.10 version, and the mfsroot.gz
is built using 4.10 objects.  If I try to boot it, this is what I 
get:

...
md0: Preloaded mfs_root "/mfsroot> 50331648 bytes at 0xc02b2794
md1: malloc disk
...
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 in isa0
sio0: type 16550A, console
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
vga0: <Generic ISA VGA> at port 0x3b0-0x3bb iomem 0xb0000-0xb7ffff on isa0
ad0: 30MB <SanDisk SDCFB-32> [490/4/32] at ata0-master PI01
Mounting root from ufs:/dev/md0c

And then nothing.  Nada.  Zip.

No kernel panic message, no prompt, nothing.

Which leaves me in a bit of a pickle as to what to try.

If I use a 4.10 kernel with a 4.8 mfsroot.gz, it boots,
but tells me that proc is out of sync with the kernel.

Help?!

TIA

rip