Created an account just to share a problem I've encountered with my 430CDT and a solution.

I've picked up the laptop in pretty good shape, it was sold as "likely missing HDD", because that's what it said in BIOS setup screen. It turned out, HDD was present, but one pin on it was corroded (likely by a leaking battery). Removing the corrosion made the laptop see the HDD but it wouldn't boot anyway despite trying and making noises, and I've replaced it with a CF card on an IDE adapter. Installed Windows 95 (by copying the installation folder to the CF card and running it from there) - everything worked fine.

Then I decided that it was time to remove the batteries which can leak (and likely already leaked some). After removing the batteries and inspecting the board I thought that everything looked good now, put the keyboard back and turned the laptop on.
Strange thing #1 - no more memory test on boot, even though BIOS setup still shows full memory size (48MB).
Strange thing #2 - Windows 95 wouldn't boot anymore, saying that it couldn't find extended memory. Booting to DOS also resulted in messages saying that HIMEM couldn't find extended memory, and all I got was 640KB of conventional RAM.

I searched the internet for awhile and couldn't find anyone with the same problem. On the contrary, I found that many people said that the laptop should work just fine without the RTC battery and the backup battery. Tried removing the additional 32MB, booting without it, putting it back - BIOS always shows correct amount of RAM, but no memory test on boot and can't boot Win95.

Eventually I found a topic "90s Toshiba BIOS Reverse Engineering" on VCFED, which mentioned, that BIOS disassembly indicated that there are some subroutines which can make the laptop skip RAM initialization after "Bad CMOS checksum" error and leaving the laptop as if it had 640KB only. So I suspected that something like that happened in my case. Author of the topic was using BIOS version 6.50, my laptop has 6.30. I suspect most people who have no problem running the laptop without RTC battery have 6.50 BIOS.

I've ordered a compatible RTC battery from Amazon, transplanted the plug from the battery that I've removed to the new battery, and installed the battery. Now everything worked fine again - memory test on boot and Win95.

I suspect, there were some changes in BIOS between 6.30, 6.40 and 6.50, which fix this problem (despite nothing like that mentioned in BIOS change log). Still, I'm not going to risk upgrading to 6.50 because I see no real benefit. Removing batteries was a good thing, of course - they both leaked inside their packaging and backup battery leaked some electrolyte through the cable and the plug, but luckily not enough to damage anything. The most surprising thing (even though I've read about it from others) is that the main battery works great and holds charge to work for really long time (Windows 95 was reporting 3+ hours of time remaining, I didn't test how much it can actually last - just played a bit and shut it down).

I hope my experience helps someone with the same problem.