A quick look at the process involved to flash a 12C508 / 12C508A / 12F629 modchip with Mayumi 4 modchip code or even MultiMode 3. The main difference being that Mayumi 4 uses the PlayStation clock / oscillator and MultiMode 3 uses the PIC chip internal clock / oscillator.
The PIC chip clock can vary in frequency as the temperature changes, this can make it an inaccurate clock source. While I have never experienced this firsthand with MM3, others apparently have. Couple that with an early batch of 12C508A chips having a slightly off clock… and MM3 doesn’t seem suitable anymore. Luckily for us those issues are long resolved making MM3 a fine choice but Mayumi 4 a slightly better one.
This particular chip was given to Dale. Kudos to Dale! I am glad to report Dale was able to successfully mod his PlayStation 1 giving him access to his backup discs! 🙂
Edit: Should probably note this was my first 4K ready video… and likely my last for a while. I don’t have the CPU power to encode or bandwidth to upload!