PlayStation Development Network

EDIT: I have purchased chip flashing hardware and no longer need this!

I'm working on a BIOS modification and I'm hoping someone can sell me a pre-flashed replacement EEPROM. It can be flashed with the nocash PSX-XBOO firmware or Sony stock.

I tried buying this board from the UK, but I need the /WE pin available for re-flashing the firmware. Lifting a pin on a pre-soldered TSOP module proved too difficult for me and I broke the /WE pin trying to isolate it.

Looking for someone with maybe an old stock 4Mb (512KB) 32-pin SOIC package that matches stock hardware, or if these never existed, maybe someone else has an adapter board for modern TSOP flash with a different layout. I'm having tons of trouble finding anything SOIC-32 so I don't know if it was just never common or what.

EDIT: TSOP flash such as a pre-flashed SST39VF040 will work too, since I've found a different adapter board on OSHPark! I'd simply prefer to not have to spend a lot of money on a programmer.

I've used a ribbon cable wired piggyback on top of the original ROM chip (with some jumper switch on the /CE line), and then you can use whatever package or socket you want. Like here: http://problemkaputt.de/psx-xboo.jpg - There's just enough space in the upper-left to put the chip there and reassemble the case. DIP chips are unfortunately hard to find nowadays, alternately PLCC chips can be also used with sockets (albeit with confusing zig-zagged pinouts).

The xboo re-flashing function in no$psx is intended for updating - it works only if the chip does already contain a working firmware with the xboo transfer protocol implemented. You'll need a programmer for the initial installation, and for repairing problems in case of installing any "non-functional" firmware versions.

A programmer is just a GPIO board with socket and some small software with the programming sequence. That doesn't need to be expensive, especially when using flash chips (that don't require any special programming voltages like eproms). There are probably some simple DIY circuits around.

nocash wrote: October 31st, 2022, 1:49 pmA programmer is just a GPIO board with socket and some small software with the programming sequence. That doesn't need to be expensive, especially when using flash chips (that don't require any special programming voltages like eproms). There are probably some simple DIY circuits around.

I'll poke around and see if there are some cheap DIY solutions for the flash memory I'm looking at (SST 39VF040), all I was seeing when just looking for dedicated chip programmers were $100+ devices. If I can find a cheap solution to flash it myself it gives me brick protection and I can just order a handful of memory chips from digikey for pretty cheap.

Would love to socket it as well but all I'm seeing are DIP sockets, SOIC packages don't really seem to ever be socketed unless I'm searching poorly.