Modify An ATI 7470 To Boot On CRT

Modify An ATI 7470 To Boot On CRT

it will behave exactly like any normal card.
This means that you will need to use system-specific methods to customize the video output from the operating system itself, provided these methods are available. It will therefore be necessary to use a software such as GroovyMame, PowerStrip or others to set the operating system to the required resolution.
This is a research project. It was possible thanks to the documentation publicly available in the Linux open source drivers (ATOMBIOS headers and hardware registers for the different asics).

Using the ATOM-15 package
ATOM-15 is quite simple to use. Simply open the bios image (* .bin or * .rom). If the BIOS format is recognized, the "Patch BIOS" button will become active.
Now select the operating ranges of your monitor by ticking the corresponding checkboxes. Then press "Patch BIOS". Hopefully, you will have a modified BIOS image (marked with the suffix "-mod") ready to work.
You can select one, two or three of the ranges provided, to suit your monitor's capabilities . Please note that ATOM-15 will always try to recalculate the native mode of each BIOS in the range which results in better image quality, from the ranges you allow it to work with.
For example:
- If both 15 and 31 kHz ranges are selected, 640 x 480 in the 31 kHz range will be calculated, to avoid using an interlaced mode.
- If both 25 and 31 kHz ranges are selected, 1024 x 768 will be calculated in the 25 kHz range, as interlaced, to avoid requiring large black borders.
Also, the ATOM-15 will always adjust the vertical frequency to fall within the 50-60Hz range. This will prevent 31kHz arcade monitors from going out of sync due to the 400 line BIOS modes having a native vertical frequency of 70Hz although their horizontal frequency is 31kHz.
For a detailed log of the native modes of the BIOS and how they are mo dificate, use the "View Log" button.

You will need third party software to get the BIOS from the video card and to restore the modified BIOS on the card. Your options are:

- ATIFlash: for MS-DOS . Download it here:

1) Boot into MS-DOS from a USB disk bootable, with atiflash.exe in it.
2) atiflash -s 0 bios.rom
3) Reboot, in Windows and use atom-15.exe to patch the BIOS, put it in your USB drive .
4) Restart in MS-DOS.
5) atiflash -p 0 bios-mod.rom
6) Restart
* Make sure you use short names in MS- DOS (8 characters + 3 for extension).
* Warning: "-p 0" and "-s 0" point to the first PCI device. Check this if you have more than one video card installed.

- ATI Winflash: for Windows. Download it here: download / ati-atiflash /

1) cd C: \ atiwinflash
2) atiflash -s 0 bios.rom
3) Use atom-15.exe to patch the BIOS .
4) atiflash -p 0 bios-mod.rom
5) Reboot
* Warning: "-p 0" and "-s 0" point to the first PCI device. Check this if you have more than one video card installed.

Using ATI Winflash is very easy being a Windows GUI, but our preference is for ATIFlash (requires creating a USB bootable MS- DOS), because from MS-DOS you can test your patched BIOS before flashing it on the card, by means of the "lbios" file, as explained below.

Test the BIOS with lbios. com is a simple BIOS loader. Load a BIOS image into your system's RAM so you can take control of your video card instead of your own ROM BIOS. You can use this tool before actually flashing the patched BIOS on the video card, to reduce the chances of flashing the card with a faulty BIOS.
It is not guaranteed, however, that a BIOS that will work when loaded into RAM will not leave the card unusable later when flashing to the actual hardware - you are warned. But surely, if the system freezes after running lbios, DO NOT flash the BIOS. Effects of lbios are not persistent, everything will return to normal after system reboot.

lbios must be run from the MS-DOS command line:

c: \ lbios romname.rom

To actually run a successful patched BIOS test, you need to switch between different modes video, both standard and VESA. For this task, I find this tool to be the most convenient.

UEFI Notes
The ATOM-15 is not guaranteed to work with the UEFI BIOS. It can work as long as the UEFI code uses VESA modes. In this case, note that UEFI will likely require VESA 1024 x 768 mode to be available.
This will be true if 25 or 31 kHz intervals are used. Unfortunately 1024 x 768 is not possible for the 15 kHz range, so this mode is disabled when only the 15 kHz range is used. In this case, entering the UEFI configuration will result in a black screen.

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