OpenGD77 CPS improvements

posted in: DMR, GD-77, Ham radio | 24

Some people have reported that the CPS is not automatically detecting the OpenGD77 com port even though the drivers have been loaded.

In an attempt to provide a workaround for this instance I’ve modified the CPS, so that the OpenGD77 support screen will show a Com port selector popup if the OpenGD77 com port is not automatically detected.

The latest version can be downloaded from here


In addition this version also remembers the last directory you opened a firmware file from, which will make it easier for users when uploading firmware to the GD-77 from this feature in the CPS

24 Responses

  1. Carlos


    Thank you very much and greetings from Mexico, as I had previously posted, I had problems with the previous CPS to read the radio, now with the new one, I read and write the radio without problems with win7 on laptop I3 ……

    There is something that apparently I am not doing well, since now having read and programmed with the new CPS, I can not have reception in any TG, I have checked if the color code, the time slot, and Everything seems to be correct, however I cannot hear any TG, (I have not misrepresented the initial confuguration where if I could previously listen to any TG in its corresponding and if I have the corresponding conversation groups).

    This happens only in digital, in analogue I have no problem, it was even a good idea to be able to enable or not the radio can be selected or not to transmit outside the amateur radio segment.

    Another thing that I have not found is the way to access the directory of individual contacts ……

    thank you very much.

  2. Roger Clark

    Can you post to in the CPS section

  3. Pablo

    Good morning, a query, I’m trying to run the radiodity hotspot in vhf and it hangs, the fireware is only for uhf or you have to change parameters. thank you very much.

  4. Roger Clark

    It should work on VHF

  5. Vincenzo

    Hi Roger,
    is OpenGD77 firmware ready to use GD77 as a pocsag transmitter?
    If not, do you have in plan it?


    Vincenzo (IZ7YKW)

  6. Roger Clark

    Its not possible to support POCSAG because the C6000 DMR DSP does not allow direct access to the audio

  7. David

    The drive google link does not work. Could you update the link, please? Thank you for your help.

  8. Roger Clark

    There is no point loading an old test version. I have subsequently updated the main version on github

  9. Mike Reiser

    Hello Roger,

    I wasn’t sure where to send this so I figured I’d post it here. I’m a blind ham and have the GD-77S as the gd-77 apparently doesn’t have speech feedback. I was wondering if the gd-77S would work with your firmware and if so, would it kill the speech feedback? If it doesn’t work with the S, could you aedd speech feedback for the menus and other things on the gd-77? Thanks,

    Mike KD5LPE

  10. Roger Clark

    Hi Mike

    The OpenGD77 firmware doesn’t work with the GD-77S at the moment, however there is some ongoing work to add voice prompts to the OpenGD77 firmware running on the normal GD-77.

  11. Mike Reiser

    Thanks Roger, I’ll add your blog to my RSS so I’ll know when it is available. It’ll inspire me to get a regular GD 77 when that is added. Thanks again,

  12. Roger Clark


    All the discussion for this is on the OpenGD77 forum, in this thread

    I don’t post updates for the OpenGD77 at the moment unless its something really major

  13. Rick

    Is there some way to know if the calibration data has been deleted in the past by the faulty “hardware reset” of some original firmware versions?

    What if the the “Device Info” only shows a blank line for S/N, CPS-Version and H-Version and Soft-Version V3.01.01?

  14. Roger Clark

    Not really…

    If its working, then the calibration probably hasn’t been messed up, but I don’t know whether there are multiple ways that the official firmware can screw up the calibration

  15. Rick

    Thanks. I now found and looked at it with the flash tool, and also think there is no way to know if the calibration data, incl. the backup copies, were only recovered using the calibration from another device. (Other than actual calibration measurements.)

    Since I have no comparison, is it normal for these devices that the S/N and H-Version fields are empty?
    Might that be a hint, maybe, if that info must have been removed?

  16. Roger Clark

    One problem is that one of the bugs in the official firmware is to copy the calibration to the backup calibration when you do a factory reset (and possibly under other conditions).
    This is a big mistake in the official firmware, as it ends up corrupting the backup calibration if the main calibration gets screwed up and the radio executes a factory reset.

    If you look at the posts by Jason VK7ZJA you can compare his calibration values with yours

  17. Rick

    Oh, very good info. I can see that values seem at leas reasonable here.

    Only thing I could not find out is if it is really normal that, looking in the device’s menu and the codeplug’s read-out basic info, both the serial number and hardware version fields are blank.

    If they are always blank by default, I guess everything is ok with the device. If someone must have deleted this info, then maybe not.
    Can you tell from your experience if blank serial number and hardware versions fields are normal?

  18. Rick

    Your screenshot from here
    and its traffic interception circuit at
    may possibly indicate that empty fields are actually the default?

  19. Roger Clark

    Those values are not part of the calibration data. They are used by the CPS to prevent users from entering frequencies outside that range.

    The CPS was originally designed for commercial users, where a administrator could lock down the frequency ranges that users could enter.

    I think those ranges may also be used by the official firmware to determine which RF section to enable for each frequency range, but I’m not absolutely certain about that, because it would be a stupid thing to do by the official firmware developers.

  20. Rick

    I was manly referring to the empty serial number and hardware version fields, though. If these fields are always empty by default, then seeing them empty is not a hint for having a calibration-bricked-device at hand, that got “repaired by copying the flash from another device and cleaning up these fields”.

    BTW, did you have the chance to see with your hardware logger how this bug or feature of simultaneous receiving and transmitting works in the original firmware?

  21. Roger Clark

    Unfortunately, my day job takes up most of the day for me at the moment, and I don’t get any free time to do any analysis on the official firmware.

  22. Rick

    Yeah… wish you a good hand at being able getting to the fun parts like that genius SFR mode.

  23. Roger Clark

    I don’t have time to investigate SFR at the moment.

  24. Anonymous

    Hello, thank you very much for your contribution to improving the operation of this cool radio.
    73 de Wojciech sq9dhp

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