Patch to fix the Hitachi H1 and H2 firmware

Patch to fix the Hitachi H1 and H2 firmware

by hamlet on 25-12-2021, 14:03
Topic: Hardware
Tags: h1, h2, hitachi, Patch, Firmware, GDX

You know the problem.
No sooner have you got hold of one of these old treasures and in full anticipation connected all your stuff to it and want to turn it on - it boots into the totally forgotten firmware.
So is Hitachi's designed masterpieces, the H1 and the H2.

The original firmware searches if a ROM cartridge is inserted in the slot 1 or 2; if no ROM cartridge is found, the firmware is executed. This sounds practical but the secondary slots are not taken into account, so if you insert a disk interface with several functions (memory expansion, Megaflash-ROM, etc.), it will not be detected and the firmware will start. This might causes a conflict.

MRC user gdx has created a patch to solve this problem once and for all.
You must replace the HN61364P ROM (IC34) from the mainboard by a 8/16K (e)eprom containing the patched firmware to fix this issue.

The files you need can be found at the MRC download database.

Relevant link:
Forum topic to bypass a firmware
H1 firmware fix.
H2 firmware fix

Media browser (2)

  • Patch to fix the Hitachi H1 and H2 firmware
  • Patch to fix the Hitachi H1 and H2 firmware

Comments (2)

By gdx

Enlighted (5993)

gdx's picture

25-12-2021, 10:28

The patch for the MB-H2 might also work for the MB-21. If anyone has this computer I can check if you dump the bios and firmware. If you don't know how I can give you a method. You need just a disk interface or a CASdrino.

PS: Does anyone know the pinout of the MB-H1 power supply output and the connector type?

By hamlet

Scribe (4105)

hamlet's picture

25-12-2021, 21:17

I will have a look for the pin out in the next days.