Firmware ROM of Panasonic MSX2/MSX2+ machines

Ascended (18704)

05-05-2017, 22:31

It looks like some of the firmware ROM dumps currently used in openMSX (and I guess other emulators too) are much too large: 2MegaByte for fs-a1fm_firmware.rom, fs-a1wsx_firmware.rom and fs-a1wx_firmware.rom. The ROMs on the motherboard of at leaset the FS-A1WX are only 256 (IC16) + 512 (IC17) + 512 (IC18) kB, in which the first 256 is the kanji font ROM and 128kB of it is the rest of the normal ROMs (BIOS/BASIC, DISK, MSX-MUSIC, SUBROM, Kanji driver). So it looks like the real firmware ROM can only be 768kB.... at least for the FS-A1WX.
And when looking at that 2MB file for the WX, it looks like it has the following layout:
0x000000-0x060000: same as IC18 (firmware), but not 100% after 0x40000
0x060000-0x080000: empty
0x080000-0x100000: about the same as IC17 (firmware?)
0x100000-0x140000: empty
0x140000-0x180000: kanji FONT (IC16)
0x180000-0x200000: empty

So, obviously the ROM dump is wrong. It contains for the 2nd half only emptiness and the kanji font ROM.

The questions:
- how was this 2MB ROM obtained?
- how does the Panasonic mapper work exactly in these machines? (Perhaps it needs this weird layout to work correctly.) Related to that: how are the ROMs from these IC's mapped into that mapper?

Any help is welcome.

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Por luppie

Paladin (864)

05-05-2017, 22:59

I do have a fysical dump of the FS-A1FX rom made with an EPROM reader from an extracted ROM IC.
Would that help ?

Por Manuel

Ascended (18704)

06-05-2017, 00:31

I already checked those out once. The FS-A1FX doesn't have a big firmware ROM it seems.

Por luppie

Paladin (864)

06-05-2017, 17:33

Here you have the physical dumps of IC15, IC16, IC17 and IC18 of a FS-A1WX

https://www.msxinfo.net/downloads/?did=233

Por meits

Scribe (6491)

06-05-2017, 19:15

This is what I extracted with some rom dumper especially for the WX which I got from Bifi quite a while ago.

Por sd_snatcher

Prophet (3499)

06-05-2017, 20:19

luppie wrote:

I do have a fysical dump of the FS-A1FX rom made with an EPROM reader from an extracted ROM IC.
Would that help ?

Yes! Any dump made with an EPROM reader from any machine will be always welcome! And they will be useful in two cases:

1) Will help the openMSX team to enhance the emulation for the said machine and make it even closer to the original

2) Will help MSX owners of the same machine to restore them if the ROMs of his/her machine become damaged for bit rotting or any other reason

Could you please send me the EPROM reader dumps of the FS-A1FX ROMs? Would you also happen to have EPROM reader dumps of the FS-A1WSX?

Por luppie

Paladin (864)

06-05-2017, 21:03

I've also uploaded the FS-A1FX Dump, it can be downloaded here :

https://www.msxinfo.net/downloads/?did=234

In the FX only IC16 is present.

Por Manuel

Ascended (18704)

06-05-2017, 21:31

luppie: your WX dumps are all 32kB, that can't be right.

Por Manuel

Ascended (18704)

06-05-2017, 22:06

Meits: so with that dumper, the firmware ROM is also 2MB... it actually results in the same kind of file as I described:

1fdd9ac748aa71890236b858dea34e94e77ffd37  A1WXFIRM.000
8a2ff3e23654dcbc98e1d09f2746433a861e1d89  A1WXFIRM.001
6a0e25f7702d492f9601748977641d3fb45fc1c6  A1WXFIRM.002
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.003
8d9b5aa9934b9dd55fccc2a7adaa82192bfd27f4  A1WXFIRM.004
c26f67e42be65d354f89bb7f015fa81903571b37  A1WXFIRM.005
5f09296416429452fda024da950e8230416039bd  A1WXFIRM.006
a13086de0d82e7fcfb78cc750e37cf267d5b6e04  A1WXFIRM.007
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.008
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.009
d7c690b0d629d941f470df8162d929ec9679c413  A1WXFIRM.00A
a840241d7ffdd45dde03aeacc621e8841421a23c  A1WXFIRM.00B
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.00C
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.00D
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.00E
7e6591cd465cbb35d6d3446c5a83b46d30fafe95  A1WXFIRM.00F

7e6591cd465cbb35d6d3446c5a83b46d30fafe95 is the sha1sum of an empty block (of 128kB).

So, the question is what that firmware ROM dumper is doing exactly. It is apparently able to get contents out of many of these ROM chips!

Por meits

Scribe (6491)

06-05-2017, 22:21

You could send me another rom dumper if you want me to try...

Por sd_snatcher

Prophet (3499)

07-05-2017, 00:57

@Manuel

I suspect that this "firmware dumper" dumps all the pages from the MegaROM that those machines have at the slot 3-3.