Linux on a 100MHz r4000 indy?

[Greg Johnson <gjohnson@superweasel.com>]

I have tried recently to get Debian installed on a 100MHz r4000 indy.
I got it to install and boot the base system, but when I upgrade to the
more recent libc6, I get Bus Errors when I run things like "ls".  I
understand that this is related to the MIPS_ATOMIC/ll/sc stuff that has
been discussed here lately.  So, I tried the fast-sysmips patch.  This
changed the Bus Errors to Segfaults.  

I also have another indy with a 175MHz r4400.  This machine seems to
work fine even without the fast-sysmips patch.  

So what's the deal?  Are the r4000 and r4400 that different?  It's my
understanding that both the r4000 and the r4400 support the ll/sc
instructions.  Should I expect bad/broken hardware on the r4000 machine?  

Thanks,

Greg