| Step | Description | |------|-------------| | | psxonpsp660.bin is loaded by the CFW’s psp-boot sequence (e.g., via flash0:/kd/psxboot.prx ). It patches the kernel’s sceKernelLoadExecVSH and sceKernelCheckExecFile calls, allowing unsigned ELF/PRX files to be executed. | | 2. Loader init | A tiny assembly stub relocates itself to free RAM (≈0x88000000) and sets up a minimal exception handler. | | 3. Emulator core loading | The stub loads psxemu.prx (the actual PSX emulator, based on the open‑source PCSX-ReARMed port) as a module and passes a pointer to the boot arguments (ISO path, cheat file, etc.). | | 4. UI & user‑mode | psxonpsp.prx provides a menu UI (via the PSP’s native graphics library) to select ISO files, enable cheats, adjust screen filters, and set controller mapping. | | 5. Execution | Once the user hits Start , the PSX emulator starts, using the PSP’s MIPS‑R4000 CPU to run the PSX BIOS (or a user‑supplied BIOS) and the selected game. | | 6. Cleanup | On exit, the loader restores the original kernel hooks, returning the PSP to the underlying CFW (or stock firmware if the user boots without it). |
The file is widely considered the "ultimate" BIOS for PlayStation 1 (PSX) emulation. Originally extracted from Sony PSP firmware version 6.60 , this BIOS was specially optimized by Sony's engineers to run PS1 Classics on the PSP's hardware. psxonpsp660.bin github
Today, it is the recommended BIOS for modern emulators and handheld devices—such as the running Onion UI —due to its superior performance, region-free nature, and broad compatibility. Why Use psxonpsp660.bin? | Step | Description | |------|-------------| | |