BIOS Replacement

Hallo guys,

afaik Bleem and VGS did not need a BIOS to run PS1 Games. ePSXe and Mednafen do need them. PCSX2 and RPCS3 are asking for BIOS files too. OK you can download BIOS for PS3 from Sony Homepage.

My question is:
1. What makes the BIOS so hard that it seems to be harder to create a BIOS replacement for the Emulator than the Emulation of commercial games and Hardware?

2. now there is another PS2 Emulator Projekt (also open source) which is trying to make a BIOS Replacement. How hard would it be to use this code in PCSX2 ? Since both seems the same OSS License it should be fine to get inspired by them.

3. What had Bleem what ePSXe and Mednafen didn't? 

Greetings

1. It's not BIOS, it's the firmware. You'd have to completely rewrite the firmware to a degree it wouldn't require using the original files anymore. That's possible but not feasible as the PS3 firmware is really complex and some modules like cellSpurs are a nightmare.

2. No idea, you should ask on their platforms.

3. If it didn't require a self dumped BIOS, then the Bleem developers wrote their own implementation of the PS1 BIOS.

3. If it didn't require a self dumped BIOS, then the Bleem developers wrote their own implementation of the PS1 BIOS.

The first stages (which were not release) used dumped bios afaik but they could not requested their customers to Dump it so they wrote their own. But my Question is: why was bleem able to do it so fast while others like Play! still in development?

Are the FW on the Sony HP full FW or just updates and uncomplete?

They probably only implemented a high level emulation of the most necessary system calls, with lots of speed hacks, to get Bleem! to run. Hence the not great compatibility and why it ran games well on a 450 MHz K6-2 CPU on desktops and the Sega Dreamcast. The PS systems also increased in complexity quite a bit with each generation.