Modchip for JP PS1?

[Vendest]

Hi, this is my first post on the forum.

I own a SCPH-5500 / UP-18 (JP) and a SCPH-7000 / UP-20 (JP) for which I have installed and swapped 2 modchip (Mayumi v4 and MM3) but could not get to load a PAL or NTSC/U game so far.
From what I gathered it is not possible to region mod a jpn PS1 regardless of the modchip and would require hardware modifications such as bios and crystal oscillator swap.

Is the above correct? or is there another way around?

I have pre-ordered a PSIO but the known lead time for this device is close to a year so in the mean time I would love to run original games from another region.

Thanks

[brill]

Japanese bios has additional bootloader verification
if you want to start a game from another region (without swap bios), then you need to change the bootloader to Japanese (patch image before burn cd-r) or use the "import player" (with Japanese bootloader), for disks with other bootloaders (Europe, America)

[rama3]

.. or change the BIOS chip for a NTSC/U or PAL one, or use an Action Replay type device to "direct boot" the game (they bypass the BIOS shell and hence, the protection).

Unfortunately, we haven't found a convenient protection fix for the Japanese shell code yet.

[Vendest]

Thanks for the information, replacing the bios chip is I think the best solution.
The system seems to supply 3.5v which limits the range of chips that can be used.
Is there a list of suitable chip? From what I read on the forum and based on datasheet 29LV040, 27C512 would work.
Thanks

[rama3]

I normally use a salvaged BIOS chip from another console.
If you have the means to burn your own BIOS, I think the pinout was standard and the voltage indeed ~3.5V (fine for 3.3V mask roms).

[Squaresoft74]

I normally use a salvaged BIOS chip from another console.

Done that a few time already but was wondering if there was some hardware mod kit available somewhere that would allow to easily install/use eeprom instead ?
(Then using X-Flash or Nocash flasher to install bios).

[Squaresoft74]

It seems this is what i'm looking for:
https://assemblergames.com/threads/ps1-bios-pcbs.68957/
Anyone here tried it ?

[Vendest]

Has the bios pinout (IC102) for motherboard UP-18 & UP-20 been mapped before?
I plan to install a package PLCC32 - SST39VF040. Not sure what to do with pin31/WE
Thanks

[Shendo]

/WE should be Write Enable so just use a pullup resistor.

[Vendest]

Thanks for your reply, I think a 10kohm resistor will work well as a pull-up.
Can I assume that IC102 pinout from SCPH-7500 is similar to SCPH-5500 / SCPH-7000 ?

[Vendest]

Wiring of the new bios went well. Next step is to install the Mayumi v4
Quick one...should I install a pull-up resistor on A19 mother board side since it is unused and in floating state?

Pictures of the new bios

Thanks

[digi]

delete

[MottZilla]

.. or change the BIOS chip for a NTSC/U or PAL one, or use an Action Replay type device to "direct boot" the game (they bypass the BIOS shell and hence, the protection).

Unfortunately, we haven't found a convenient protection fix for the Japanese shell code yet.

I have a project in the works that will bypass the region lockout on Japanese shell versions. It includes other features though. For example for the Japanese consoles it will restore the CD Player menu swap trick for booting Unlicensed or Import discs and depending on the firmware version of the CD-ROM controller it can also fix the ToC for proper CDDA playback. The same project will also have features for American and European consoles.

[masterg0r0]

That's nice to know. Is there any progress on the project by any chance?

[MottZilla]

It's in testing right now. The region lock and cd player menu swap trick are working. The current hold up is fixing the ToC for CDDA tracks to play properly. I'm hoping to have that resolved very soon. I did not mention yet that it is an Expansion ROM (ex: GameShark) that does these things. So you would take a Cheat Cartridge that has a EEPROM like GameShark and flash this onto it. It will work for all console regions. The American and European consoles will have the secret unlock and boot CD-Rs and Imports just like if you had a modchip installed. The Japanese and Asian (ex: SCPH-7003) consoles get the CD Player swap trick restored, region lock removed (asian units never had it), and CDDA audio fix.

All this happens without changing the appearance/behavior from the normal system. So you still have the same boot up screens and sounds.

If for some reason you had a Japanese console with a modchip you could use this in combination just to remove the region lock so you don't need another disc to boot Import discs or require patching CD-R to have Japanese License data.

I will make a topic when it's ready.

[masterg0r0]

Ok, sounds good.

[MottZilla]

It's released and details are here:
https://www.psxdev.net/forum/viewtopic.php?f=66&t=3966