No problem bro, take your time. So if I understand correctly the ubuntu 12.04 packages were compiled for the armel/thumb2 platform. And the cpu of the N900 does not support thumb2 instructions. To work around this issue we have to enable the errata_430973 fix inside the kernel to be able run excutables with these thumb2 instructions compiled.
But you said the errata_430973 fix was enabled in previous versions of KP (for the sake of running these thumb2 binaries?). But didnt anyone tested if this would really set the bit?
We can always recompile the complete 12.04 userland without thumb2 I guess If anyone willing to provide the hosting/storage/cpu-cycles that is...