Ok. I've made a umsdos-2.4.9-4 patch that seems to fix all known 2.4.x issues. It is against 2.4.9 kernel.

There are some changes that got in 2.4.10pre, so it will not apply cleanly against that. Use this umsdos-2.4.10pre2 patch if you use one of those. Documentation is still not up-to-date, but I'm working on that. Patch against 2.4.10pre2 was sent to Linus, so I hope for inclusion in 2.4.10 when it comes out...

OK, here is one test-patch: it is really a kludge, and only a half-functional one at that, but I did manage to boot with init=/bin/sh with it! It dies a little while later, but it's a start. Could you people please test umsdos-2.4.0-kludge1 ? It is against 2.4.0 release, but should work for few versions up and down.
This one tries to fix: For non-boot use, it should be mostly OK (only minor issues AFAIK, see [somewhat outdated] Known problems)
Biggest problem is that UMSDOS pseudo-root does not work (so you cannot use UMSDOS as your boot partition). I'm trying to work on it, but it is extremely difficult (no tools to debug this type of problem, only bunch of printk's). If you have any ideas/suggestions/help, I'm open for it! I've tried usermode-linux patch, but it fails to compile for me for 2.4.0. And it seems to modify behaviur anyway.
Get a small patch here to fix compile problems in test6 and test7 (or wait for test8 - hopefully it will make it in by then).
Get 2.4.0-test5i diff against 2.4.0-test5 (or test3/test4 if you don't like test5).


here is quick fix for OOPS on write problem in 2.4.0test3 and newer -- at least it doesn't OOPS any more, although I think I've seen strange things happening (created directory is not seen, but new attempt to recreate it give EEXIST, and after a while it automagically appears). I'd appreciate all bug reports on 2.4.x kernels, no matter if you already reported it or not -- just to make sure I don't miss anything.

Here is umsdos-2.3.41g patch against clean 2.3.41 kernel (actually, anything between 2.3.32 and 2.3.42 - for 2.3.x kernels older than that try looking here). It is port of umsdos-2.2.14g patch to 2.3.x, so look above to see what it fixes.