AIX 4.1.3 on 7009-C20 RS/6000

Any RS/6000 hobbyists out there? I got my old 7009-C20 pretty tricked out and hardware carefully selected to be compatible with AIX 4.1.3, the version I'm trying to get running on it. Unfortunately, I can't get the dang thing to boot my 4.1.3 or 4.1.4 CD's. It'll boot my 4.1.5 disc, however. The 4.1.3 and 4.1.4 CD's are labeled "AIX for clients" or something like that, and I seem to recall having trouble getting other RS/6000's to boot from this 4.1.3 CD, even though it's genuine original media, and reads just fine in a working system. Anyone know a way to check what systems an old AIX 4.1 disc supports, or have C20 or similar MCA machine running 4.1.3? My other thought was to try to NIM boot it using my ThinkPad 860 as a NIM server (running 4.1.5), but it unfortunately doesn't have enough capacity to hold a lpp_source and a SPOT, and even then it looks like the 4.1.3 disc may not have enough stuff on it to support the C20 anyway... Anyway, thanks in advance!