This zip contains a BIOS pack for the Toshiba T5200

To see which original BIOS version is installed on your T5200, run TEST3.EXE and select option 8 - System Configuration

Original BIOS (27C1024)
This contains the original unmodified BIOS versions found so far:
T5200 BIOS V1.20 (Award).BIN - this version will not detect 8MB memory SIMMs
T5200 BIOS V1.30 (Award).BIN - a fixed version of the above
T5200 BIOS V3.00 (Phoenix).BIN - Toshiba switched to using a Phoenix BIOS for this release
T5200 BIOS V3.10 (Phoenix).BIN - Only difference is the removal of the string "FOR EVALUATION ONLY"
T5200 BIOS V5.30 (Award).BIN - Most recent version found so far

The Award V1.xx versions are the only ones that will boot from any HD without any patches and thus allow drive overlay software to run, later versions will refuse to boot any drive that doesn't match the BIOS setting and will only work with an external boot ROM such as XTIDE.
 
VGA BIOS (27C256 on separate VGA card accessed from the ISA bus slots cover)
T5200 VGA BIOS 1988 24K 27C256 1.04 01.BIN - Original VGA BIOS
T5200 VGA BIOS 1989 32K 27C256 1.04 09.BIN - Updated VGA BIOS occupying 32K instead of 24K
T5200 VGA BIOS 1991 24K 27C256 1.04 01 (Identical to 1988).BIN - a re-release of the 24K BIOS identical except for the date
It's possible the 32K VGA BIOS contains extra character sets for European languages and maybe bug fixes/improvements

NOTE If your T5200 has the 32K VGA BIOS you can only use the V3.xx Phoenix or V5.30 Award BIOSes as the V1.xx Award versions will not boot with it installed.

The patched versions of the BIOS have the following changes:
Built in XTIDE to boot from any HD
Auto detect and configure CX486DLC, CX486DRx2, TX486SXL & TX486SXL2 386 to 486 upgrade processors
(Includes detecting if hardware mods have been made to improve speed of those processors)
Fix an issue that stopped formatting 1.44MB discs on some machines with DOS version 4 or higher
Support external 3.5" 1.44MB instead of 5.25" floppy drive on the printer port (useful with a GOTEK floppy emulator)

There are two alternative versions of the patched BIOSes with different versions of XTIDE universal BIOS.
1. HIMEM 639K
This is essentially a minimal but otherwise standard 386 build of XTIDE with some minor tweaks to make sure windows 95 doesn't run in MSDOS compatibility mode and Windows NT doesn't blue screen on boot.
This version reserves 1K at the top of conventional memory for it's workspace leaving 639K free for the OS which is the same technique used by drive overlay software.
Unfortunately, this technique is not compatible with Windows 2/386 or Windows 3.00 in 386 enhanced mode and they will crash if you try to run them.
The problem was fixed in Windows 3.00a and later.

2. LOMEM 640K
This version is a modified version of the 386 build of XTIDE which uses workspace in low memory at 30:0 and some unused BIOS workspace at 40:0 instead.
It will run all early windows versions and has the full 640K available to the OS.

The LOMEM version was made so it would be possible to boot all early versions of windows on a multiboot setup using grub4dos.
However, this version might have unknown compatibility issues with any software which makes use of the same low memory workspace which is why the HIMEM version is included as well.
(Some BIOSes of the early 90s had a configurable option to switch between using similar HI and LO workspaces for the same reason)

Patched files are:

T5200 BIOS V1.30 (Award) patch 1.2 with HIMEM XTIDE 639K.BIN
T5200 BIOS V3.00 (Phoenix) patch 1.2 with HIMEM XTIDE 639K.BIN
T5200 BIOS V3.10 (Phoenix) patch 1.2 with HIMEM XTIDE 639K.BIN
T5200 BIOS V5.30 (Award) patch 1.2 with HIMEM XTIDE 639K.BIN

T5200 BIOS V1.30 (Award) patch 1.2 with LOMEM XTIDE 640K.BIN
T5200 BIOS V3.00 (Phoenix) patch 1.2 with LOMEM XTIDE 640K.BIN
T5200 BIOS V3.10 (Phoenix) patch 1.2 with LOMEM XTIDE 640K.BIN
T5200 BIOS V5.30 (Award) patch 1.2 with LOMEM XTIDE 640K.BIN

Note there is no patch for Award V1.20 as it has memory SIMM detection bugs
