PS2 BIOS mod

Discussion in 'Sony Programming and Development' started by HI_Ricky, Dec 3, 2017.

  1. HI_Ricky

    HI_Ricky Peppy Member

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    in year 2000, PS2 use hi tech fast ROM and system set boot have time out,so it hard replace / full mod
    today we have fast and easy good FPGA/ flash,
    is any good way or idea to build / mod PS2 bios ?
     
  2. WorldGenesis

    WorldGenesis :D

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    I mean the BIOS is held on a ROM, perhaps like the Dreamcast, there's a way of piggybacking the ROM chip :O
     
  3. sp193

    sp193 Well Known Member

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    But there isn't really a purpose for replacing the boot ROM because it doesn't really do anything that region-locks.

    This is what modchips do.
     
  4. truemaster1

    truemaster1 Peppy Member

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    sure modchips eliminate region checks, but what about some special features more than region checks? more stylish menu. regognise an hdd larger than 137 gb even unformated without the spinoff. and have browser 2.0 without the known image by only with fhdb. and even more that i cannot think right now. but sure is one thing with moded bios new things can arrive. also with fmcb or fhdb modchip is a thing of the past. some ps2 users have already a psx only modchip so a region free bios will be good for us
     
  5. rama

    rama Peppy Member

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    The problem is that you can't just swap the BIOS and be free from all the protections.
    Some protections are in different chips and they check each other.
     
    truemaster1 likes this.
  6. sp193

    sp193 Well Known Member

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    These are not features of the PS2's ROM browser. To achieve such a thing, the browser has to be replaced.

    In fact, there is already an update mechanism for replacing the browser and/or to apply patch(es), which is used to boot FMCB and FHDB.
    Right now, FHDB/FMCB are not drop-in replacements for the browser, but you can implement such a thing...

    There is also another gotcha to replacing the ROM: there is boot certification, for consoles starting from the SCPH-30000 series. The ROM version, region and type will be passed to the MECHACON at boot. If it's wrong (i.e. because the ROM was replaced), then the CD/DVD drive will be left unoperational.

    I have once found a bcertifyH.irx module (for the PSX, if I remember right), which seems to do boot certification in a universal way. It obtains the ROM version, but brute-forces the region and type letters. But it goes to show that even Sony was constrained by their own rules that they laid down for the MECHACON (not the ROM).

    FHDB isn't related to the HDD Browser v2.0 update. In fact, FHDB isn't an image.
    If you installed FHDB via somebody's HDD image, then that isn't the proper way to install FHDB either. It's supposed to be installed with the FMCB installer.

    It's not region-locked in the ROM. Yes, there is some region-locking in the form of checking the PS2 logo on the disc, but that is not something that must be done to boot a disc. The true region-locking is done on the MECHACON itself.

    It's pretty clear that Sony intended it so that it is possible to remove/replace the software-based restrictions. To a point where the ROM doesn't actually require a PS2 HDD (it can support generic disks totally fine, unlike all installable Sony software).

    You can boot your own update from the memory card, flash storage or HDD unit, and you can do whatever you want with the console... really. You don't need to change the ROM because it already provides an easy way for the browser to be replaced and the browser also has full control over the console (like with any game). This mechanism is not board-specific either, unlike the ROM image itself.
    This is why I don't call it a BIOS, as it doesn't do basic I/O. The service manual does not call it a BIOS either, but labels it as "BOOT ROM".

    ***

    But that being said, there can be a use for modding the ROM, although most people probably won't need such a thing.
    TOOLs have DECI2 modules in their flash ROM images, which provide complete debugging functionality.
    CEX and DEX units have ROMs that are missing all DECI2 IOP modules, and their EE kernels have a DECI2 stub that does not support all commands. RDB allows debugging to be done on DEX and CEX, like the TDB startup card does... but there is a difference (also shared by the TDB startup card): you cannot reboot the IOP at all. It also implies that you cannot boot other software with LoadExecPS2 either, as that reboots the IOP.

    It is likely possible to introduce replacement DECI2 modules into the IOP, like those that I came up with for RDB, optionally replacing the EE kernel with one that supports all DSEDB commands too. All so that debugging can be more easily done, as on a TOOL. However, you're still constrained by the memory that a mere CEX console has.

    But well, I strongly believe that this isn't a very strong reason either, as you could probably come up with a REBOOT module that conducts any IOP reboot with the necessary modules from a memory card. This was previously done by RDB-UIF-RB, to allow IOP reboots to be done (hence breaking free of even the restrictions of the TDB startup card).

    So the only advantage of such a mod, would be to be free of memory cards.
     
    Last edited: Dec 7, 2017

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