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twistedpneumatic
October 26th, 2017, 08:36 AM
Is there a better BIOS I could put in my Metalis 286. It has the BIOS on a little daughter board so I could replace it. Can I replace it and hopefully unlock the 60MB HDD limit?

Krille
October 26th, 2017, 10:48 AM
Can I replace it and hopefully unlock the 60MB HDD limit?

There's no need to replace the system BIOS. Just install a copy of XTIDE Universal BIOS.

Caluser2000
October 26th, 2017, 11:15 AM
You can use Dynamic Drive Overlay software to get around the bios limit as well.

David_M
October 26th, 2017, 12:47 PM
I recently had a 286 system with a faulty bios and found the the best solution was to put a working copy of the same bios back into the board. The keyboard controller often doesn't play well with a bios from another vendor.

I also used an old network card to host a copy of XT-IDE (AT) to overcome the drive table limitation.

mR_Slug
October 26th, 2017, 03:48 PM
You may be able to get by with another BIOS, but I would check that it's for the same chipset. Also this is a laptop right? If so, I would also recommend the Dynamic Drive Overlay software.

RuudB
October 27th, 2017, 05:06 AM
There's no need to replace the system BIOS. Just install a copy of XTIDE Universal BIOS.

May I point you to my site: A bigger hard disk drive for your 80286 PC (http://baltissen.org/newhtm/pc286upg.htm)? It describes a hack to add the XTIDE BIOS to the existing BIOS. Condition: you must have at least some 12-16 KB of free space on it. And yes, it describes the hack for this type of Commodore PC but the general idea should be clear

Be careful, it is not something done in a few minutes and yes, it describes the hack for this type of Commodore PC but the general idea should be clear IMHO.

Have fun!

SomeGuy
October 27th, 2017, 05:47 AM
There are some "generic" IBM AT compatible BIOSes listed here: http://www.minuszerodegrees.net/bios/bios.htm The AMI bios allows custom drive types.

To use a generic BIOS, your 286 must be 100% IBM AT compatible internally.

You should also consider editing the drive types in your existing BIOS. Of course you will need an EPROM programmer and some extra EPROMS. Personally, I would consider that the "cleanest" solution with the lowest probability of compatiblity issues. I think there were some tools to help with that, but it is mainly a matter of editing a few bytes in a lookup table,recalculating a checksum, and on a 286 splitting back up in to HI/LO roms.

If you dump and post the ROMs perhaps someone can help out with that. And it would be good to archive the ROM set.

Krille
October 27th, 2017, 05:49 AM
I could either calculate a new checksum or disable the routine. The last was the most simple solution by replacing a 'je' command (Jump if Equal, read: jump if checksum is zero) by a 'jp' command (JumP). Again changing only one byte.

JP means Jump if Parity which is not the same as an unconditional jump (JMP). BTW, I would just update the checksum instead of disabling the check.

twistedpneumatic
October 27th, 2017, 05:58 AM
I will try the Dynamic Drive Overlay thing and see how it works. It only supports 20,30,40 and 60MB preset drives. No CHS settings listed but it will recognize other drive types but only the ## drive types (1-37)