kernels I build just won't boot, what's the trick?

[Martin Gelfand <gelfand@lamar.ColoState.EDU>]

After much head-scratching and teeth-gnashing (mostly involved
with the bootstrap process) I managed to install 2.2r2 on an
LX164 machine (533MHz 21164A, 256Meg, ncr53c875 controller
for an all-scsi system, DECchip ethernet) which has an 
AlphaBIOS console.  I then promptly upgraded it to woody.

The problem I am having now concerned custom kernels.
The generic 2.2.18pre21 and 2.2.20 kernel images work
fine.  However, taking the 2.2.20 source and the config
file associated with the generic image, changing only the
subarchitecture (?) from generic to lx164, gives a kernel
which just won't boot.  No problems compiling, fortunately,
but MILO just complains that the kernel can't be booted, period.
(If anyone wan't the exact error message I can cause it
to be generated again, but it really didn't have more information.)

Is there any "magic" I need to know about to make an alpha
kernel bootable via MILO? 

Thanks,
Marty Gelfand
Dept of Physics, Colorado State University