Both the v2.2.13 kernel and v2.3.16-v2.3.21 seem to work fine with MCA. v2.3.22 isn't stable on any platform. v2.3.23 and onward has BIG problems on MCA-machines, probably due to the great boot-code and memory handling rewrite. I have however only tested these kernels on my PS/2 56slc2 (9556) with 2 SCSI-drives and a 3c529 network-adapter, so your mileage may vary.
I have included a patch here which makes its possible to boot the latest series of v2.3.xx kernels, but it's a real KLUDGE; as it turns off panics if commands fail (usually a hardware error, but in this case probably a problems somewhere in the driver.) This is a TEMPORARY and EXPERIMENTAL fix, that might even corrupt your disks (however VERY unlikely.)