Those simms are ludicrous 🤣, they barely fit in the mobo, they are so thick that they touch each other once installed.
I made good progress tonight.
I tried the replacement HIMEMX.EXE and it does not give me the error and works just like himem.
I dont think the error is due to a bad stick anymore since it does it with 3 different pairs of simm. Seems more likely it is some sort of 3some incompatibility with the system, himem and the 72pins ram.
I cannot tell if my sticks are parity or non-parity. I am gonna try memtest86 and see if i get a problem with that but so far, system seems happy.
I also ditched my 1.6 gb hdd and scrounged a 6.4 gb fujitsu drive that i trust more. Maxblast would not let me format more than one partition of 2gb ( or i did not find out how) so i used ontrack disk manager instead. Not as user friendly as Maxblast but i managed to format my drive in 4 fat16 partitions with it.
I now have 6.4 gb on my 486, the dynamic overlay does not even take any conventional memory. It also allows you to boot from cd when pressing spacebar. Did not test if this feature works on a 486, but that is still great! Just make sure you have a mouse connected when you install it, its a graphical thingy and has a glitch at one of the screen that you cannot get past with only KB. I had to reboot and go on a hunt for a serial mouse the first time 🤣
Tomorrow ill start to screw the computer back together as im pretty set on the hardware at this point.
One more thing you guys can probably help me about is tweaking the bios. I did the basics (hard drive, floppies, time/date ... ) but did not touch anything else, its all reset default. Might be that the Parity glitch with himem is fixable with bios ? Anyway here are two screenshots of the advanced settings. There are several options that i do not know about. My favourite one being : Single ALE enable : no ( i usualy drink more than one )