I would run the mtest on a large region of memory to make
sure the memory controller is configured correctly.  If not,
you could be aliasing memory.  Been there.  Done that.

Regards,

Russell

>
> I have 8 MB of RAM (I have more, but have configured u-boot to
> recognize just the first 8). Kernel is 2.3 MB (0x244086). I load it at

But this is NOT the size of the _compressed_ image???

> an offset of 4 MB in the SDRAM space... should be enough for
> everything, I assumed. I'll have to check this again.

Did you actually use 4 MB (400000) or did you use some other  address by  accident? What is your exact boot comand, and which output do you get?

Best regards,

Wolfgang Denk