Hmm, no that's not right. According to [wiki](http://en.wikipedia.org/wiki/MIPS_architecture) "Each revision is a superset of its predecessors.", so mips-1 code should work on mips32. Maybe the device sees the mips R3000 Machine header and refuses to run it? That would be strange indeed. You might try changing that to refer to a mips32 release. Or pulling a binary from the device and comparing the two.