Have you used a microscope to inspect the memory sockets for damage?
I recently flashed my bios from A02 to A05 on a Dell L433c w/ 512MB RAM (256 in each of the two slots). Immediately after, system failed to boot because only 4MB RAM was recognized on POST.
Repeated tries showed 16 or 24, but never enought to boot Win 98SE. If I remove one DIMM, system boots normally. In fact either DIMM in either slot works normally, but not both together.
I took out one of the DIMMs and successfully flashed back to A02. Now boots normally. Reinstall second DIMM and have SAME PROBLEM! I guess it's not the BIOS after all. If I put either DIMM in either socket, machine works normally; if I put in both, neither A02 nor A05 BIOS will recognize more than 24 MB of RAM. Problem began immediately after the first BIOS flash. I'm starting to think about some kind of secondary chip or mobo damage. The diagnostic lights show all 4 green. Any ideas?