1541 Ultimate-I Firmware

Obliterator918’s custom 1541 Ultimate Firmware for “mark 1” units.

A "mark 1" 1541 Ultimate. (Wikipedia Commons.)

A “mark 1” 1541 Ultimate. (Wikipedia Commons.)

If you have a 1541 Ultimate “mark 1”, my firmware may be of use. Since Gideon is developing new firmware revisions to take advantage of the larger FPGA on the Ultimate-II, official releases for Ultimate-I units have ceased (at least as of this writing).

Since the firmware is open source, I was able to make a custom build for my Ultimate-I with more recent additions than the last official revision for the Ultimate-I. I’m more than happy to share it here.

Version 2.6d.O918.4 Based on Gideon’s SVN revision 131.

Download: 1541-Ultimate-MK1-2.6d.o918r4.zip

Place appl.bin in your sd card root. It doesn’t flash your device, so it’s safe to experiment. You can revert to your official flashed firmware by simply deleting the appl.bin file.

For anyone else who wants to work with any of my revisions, the o918.patch file contains the only modifications I made to the firmware source.

Important features of this firmware revision:

  • File viewer (great for reading the VERSION.NFO files reformatted by the GameBase 64 Reorganizer)
  • Integrated SID player
  • All fixes and compatible features up to official firmware release 2.6d.

My changes and additions:

  1. Added F3 help screen to show 1541U commands.
  2. Modified the file viewer so that scrolling will not advance past the last line.
  3. Added F1 and F7 page up/down to the file viewer.
  4. Modified behavior of the file browser so that when you cursor-right on an item with no children, the context menu is brought up as if you pressed return.

14 thoughts on “1541 Ultimate-I Firmware

  1. Eidis

    Thank you for your hard work and dedication. After a long time of waiting for updates found your firmware and it works like a champ ! Best of luck in your future projects and may God bless.

  2. Brian Popilek

    I just bought one of these off of eBay and I am excited to get it. I know there are more features on the Ultimate-II, but mine has the ethernet port and that is a big plus for me. I was just curious, since it has been quite awhile since your last firmware, if you had any plans to update the firmware any more? Or, do you think it’s as good as it can get? Thanks for all of your hard work! I have saved your firmware file and plan to use it when my unit gets here.

    1. Obliterator918 Post author

      I don’t have any plans for further development of the firmware. It’s pretty much maxed out. I’ve experimented with trying to enable additional features from the mark-2 firmware but there is just no room left.

      I have not tested my firmware on units with Ethernet. It’s been a while since I looked at it but I don’t think that Ethernet support is in this fork of the firmware.

  3. Pingback: GameBase 64 Reorganizer SD version 4 released | Obliterator918's Commodore 64 Project Haven

  4. Andry

    Thank you for this firmware update. It pretty much saved my ass for a demo show recently. Great work and glad to know, my hardware is used to the maximum 🙂

  5. Andreas

    One question. Can this unofficial firmware be also used on 1541-Ultimate1 versions from the very first batches back then. I have one of these, without REU and so on, cause i bought a 1541U directly in 2008 when it came out. So far, i use firmware V1.72b, which is also some kind of an unofficial one, because it is based on the official V1.7 firmware. When the V2 firmwares were introduced back then, it was said, that i can’t use these firmwares and that i must stay with V1.7. Then somebody introduced V1.72b and i used this, since today.

    I was actually never dissatisfied with V1.72b, as far as disk versions of demos or games are concerned (almost everything runs normally there), but what I always found a pity, was, that there were many newly released games that came only in cartridge-format (like “Prince of Persia” or “Soul Force” etc) that I could not start on my 1541U1 with this V1.72b.

    Therefore, if this unofficial firmware here now allows that, an update would of course be a good idea. I just want to make sure, my very old 1541U1 from the very first batches, is capable of handling this firmware here, hence the asking.

    Short reply would be great. Thanks in advance, best regards.

    1. Obliterator918 Post author

      I can’t say for sure. My Mark-I unit is pretty old and it works. Also, it doesn’t require a flash to try it.

  6. Andreas

    Thanks for the fast answer. You are right, there is no risk, when no flash is required. I will try this out on next weekend on my MK1 and later report, if it had worked.

    One last question, because i have no experience with the V2 firmware versions of the 1541U firmware and this then would be a V2 firmware. Is it possible with your Version 2.6d.O918.4 then, to let games which are only available in cartridge-format, like for example “Prince of Persia” or “Soul Force”, run on a 1541U1 then? This had never worked with V1.72b and while i was always satisfied with the compatibility to software in disk-format, it was always sad for me, that i could not play these mentioned two crt-games on my real C64 with my 1541U1. If this would work then, it would be fantastic.

    1. Obliterator918 Post author

      I honestly don’t recall. It’s been a long time since I used this revision of the Ultimate 1541.

  7. C64Ever

    Hi, I am trying to extend the firmware of the Ultimate 64 and looking for a non-invasive way to try out changes without actually flashing them. On your page here as well as in Gideon’s Github 1541 repo (doc folder), I read that one can rename “ultimate.bin” to “update.bin” and place it in the root of the SD card. This applies the modified application without actually flashing it.

    However, there is no SD card reader on the Ultimate 64. Instead, it has 3 USB ports and a built in Flash disk. I connected two USB drives and I placed a custom built update.bin on the two drives as well as in the root of the Flask disk. But it’s not getting picked up after a reboot. Any ideas?

    Also, Gideon published a recovery ZIP archive for firmware version 1.22. It contains a SOF file for Intel’s Quartus FPGA programmer tool, as well as several bin files (for cartridges, etc.) and a swp file. Do you know what these bin and swp files are for? I got an FTAG cable and got the Quartus software ready to go in case I brick the device by actually flashing my custom firmware, but the Quartus software doesn’t allow one to select bin and swp files to flash to the FPGA – only the SOF file.

    Thanks a lot for your help. I already reached out to the Commodore Reddit channel and to Gideon directly, but have not found a solution yet.

    1. Obliterator918 Post author

      As far as I know, the U64 doesn’t allow you to boot with an alternate firmware from a file. You have to actually flash it. I don’t know the answers to your other questions. The 1541-U firmware project toolchain is probably very different from developing for the U64, and that was 10 years ago anyway, so I can’t remember many details.


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