List of Radioddity GD-77 bugs

posted in: Ham radio | 53

With the release of the new beta firmware for the GD-77 they seem to have fixed a few bugs but also introduced a few new bugs, and as I can’t find a comprehensive list elsewhere, I thought I may as well post a list myself…

Note. These are just bugs in the GD-77 firmware not problems in the CPS (as I have fixed numerous bugs in my version of the CPS)


Firmware bugs


  • Alphabetic character input for new contact does not work correctly (firmware 3.1.0 beta only)
    When adding a new contact directly into the GD-77 via the keypad, the alphabet and number characters being entered do not match the legend on the keys.
    Note. Thanks to Douglas for reporting this problem.
  • ActiveClient does is unable to connect (3.1.0 beta only)
    ActiveClient (DMR ID library) utility is unable to connect even when the correct 3 button sequence is used when turning on the GD-77
    If a the GD-77 already contains a DMR ID library uploaded using firmware version 3.0.6 it continues to work, but its not possible to update the DMR ID library.
    Note. I have investigated this issue, and the firmware does not seem to be checking for the three button sequence and is starting in its normal operating mode, where the USB can only be used to update the codeplug. Hence when ActiveClient requests the “Version” number of the DMR ID library, which needs to be 001, the GD-77 instead sends back data empty data, as access to memory outside the codeplug region (the first 128k of flash memory) is blocked unless the GD-77 is in DMR ID mode)
  • Factory reset bug. (firmware 3.0.6 & 3.1.0 beta)
    Factory reset seems to put invalid data into various places inside the GD-77.
    One serious side effect of this is that the Pa power seems to be set to virtually zero, and this setting can’t be updated via the codeplug.
    Consequentially if your GD-77 decides to do a factory reset, or if you manually do a factory reset in either firmware 3.0.6 or 3.1.0, the only fix is to downgrade to firmware 2.6.6, reboot the radio and then upgrade back to 3.0.6 or 3.1.0
  • Dual Capacity Direct Mode, “Uncommanded transmit” bug (firmware 3.0.1 only — Appears to be fixed in 3.1.0 beta)
    If a VFO is set to Analog mode, and Dual Capacity Direct Mode is selected, then the VFO mode is changed to Digital, the GD-77 will automatically transmit if it is left unused for a few minutes (I don’t know the precise time before it starts to transmit)
  • Promiscuous mode causes “All call” to be displayed (Firmware 3.1.0 beta only)
    In Promiscuous  mode (aka Monitor mode) when receiving a DMR signal, the display shows “All call” rather than the Talkgroup of the incoming signal.
  • Rx Group list must not be set to None in the CPS (all firmware versions)
    Although the CPS allows “None” to be selected as an Rx Group, doing so stops the GD-77 from receiving any TG’s or ID’s at all.
    The None option in the CPS should probably not be there at all, or if it is, the firmware should interpret this as All TGs aka promiscuous mode.
  • In VFO mode, the Rx Frequency locked after changing channel mode to Analog using the GD-77 front panel menu. (all firmware versions)
    When this happens, the the GD-77 appears to function correctly, and it appears that the Rx frequency can be changed, or that a scan can be initiated, however the GD-77 does not change its Rx frequency.
  • Scan list displays blank scan names on display (all firmware versions)
    If a channel with number greater than 256 is used in any scan list the display on the GD-77 gets corrupted such that many of the names of the scan channel groups are not displayed at all.
  • Invalid channel displayed when scanning in “single wait mode” (all firmware versions)
    When scanning, the GD-77 will stop when it detects a signal, and everything appears to be working, as audio can be heard, but the display shows the default Tx channel, rather than the channel which the GD-77 is receiving on.
  • VFO scan (search) shows “Scan is invalid” if selected from the menu system (all firmware versions)
    Note, it is possible to do a VFO scan, but only if the CPS is used to assign a button press to this feature.
  • Colour Code Free – Admit Criteria (all firmware version)
    When using Colour Code Fee; under some circumstances its not possible to transmit even when a channel does not actually contain any traffic.
    The technicalities of this are that when a base station (repeater) continues to broadcast the carrier and “Terminator LC Frames”, it is not possible to transmit, because the GD-77 is only checking the “timslot busy flag” and not the contents of the traffic on the timeslot.
  • Talk permit tone not functioning (version 3.1.0 beta only)
    The GD-77 can be configured to beep when a channel becomes free after the other station finishes their transmission.
    This feature is completely broken as the beep occurs even when transmission is not possible.
    Note. This feature is enabled on the General Settings screen in the CPS.
  • Audio codec hangs causing “aarrhhhhhhhhhhh” to be heard continuously (all firmware versions)
    Occasionally the received audio will have a glitch such that the last decoded frame of audio is continuously repeated. This continues until the incoming signal is stops transmitting or the channel is changed or the GD-77 is rebooted.
    This bug does not seem to effect all GD-77’s and is probably caused by a calibration error
  • Incorrect Tx Conact ID used when the contact “number” is greater than 256 (all firmware versions0
    If a Channel uses has as its Tx “Contact” a Contact with its number being greater than 256, the GD-77 incorrectly places a call to a different contact, i.e it sends a different DMR ID as the destination ID.
    Note, I presume this is because the firmware only stores the TX Contact reference number in one byte, and hence if a Tx Contact with number 257 is request it would use the ID of the Contact number 1
  • Green Rx signal indication LED does not illuminate when receiving a signal when scanning in DMR mode (all firmware versions)
  • When the GD-77 is first turned on, if the receive frequency is in use, the green LED comes on but the DMR ID is not displayed.
    However if you change to a different channel and then back to the channel thats in use, the DMR ID is displayed.
    Hence I presume that the ID of the station that is being received is not just sent at the start of the transmission and its just a bug in the firmware which is preventing the display to be updated to show the DMR ID or the details for the associated Digital Contact, if that ID is in the Digital Contacts
  • Under some conditions “Ch Empty” when selecting a channel. I suspect this is partially a bug in the CPS where it does not correctly delete a channel and instead leaves an empty slot in the Channels data area.


Less than optimal firmware functionality

  • Cross band operation (e.g. Tx on 2m and Rx on 70cm or vice versa) is not officially supported, but partially works, with reduced power output.
    There does not appear to be a technical reason why the transceiver can’t operate cross band, if the Tx frequency is used to configure the Rx power rather than the Rx frequency.
  • Battery meter is no very useful.
    Batter meter on the screen reads 3 bars when fully charged, but if the PTT is keyed, this drops almost immediately to 2 bars, even if the battery voltage was 8.4V prior to pressing the PTT.
  • Signal meter is virtually useless
  • Squelch settings if “Normal” and “Tight” are not adjustable, which makes it impossible to communicate with stations with weak signals unless Monitor mode (open squelch in Analog mode) is enabled
  • Receiver can be overloaded by strong signals.
    Some transceivers which use the same receiver chips (AT1846S) do not seem to have this problem, so this appears to be a settings issue which could be corrected or improved by a small change to the firmware.
  • Its not possible to possible to default to Monitor mode (Promiscuous mode) in either Digital or Analog mode.
    Ideally it should not be necessary to set an Rx Group at all for a channel and it should allow reception no matter what the TG or ID of the received signal was.
  • GD-77 needs to be put into DMR ID (ActiveClient) mode to update the DMR ID library
    This seems to be an artificial limitation as the USB protocol sends the Codeplug and the DMR ID to completely different parts of the flash memory.
    So it would be possible to build the functionality of ActiveClient into the CPS and upload without rebooting the GD-77 and holding down the 3 buttons, if a change was made to the firmware to allow this.
  • When in VFO mode, the up or down arrow has to be pushed repeatedly to change the frequency in small steps. Ideally if the arrow key was held down, after a short delay the key should “repeat”, so that it possible to change frequency by holding down the up or down arrow until the required frequency is reached.
  • When switching from zone to zone the channel number from the previous zone is used in the new zone.
    I don’t think this is ideal, it would be better if the firmware stored the current channel when in each zone, and switched back to that channel when you go back to a zone you have previously used and changed channel in..



  • Charger incorrectly charges batteries to a higher voltage than should be allowed for the type of lithium batteries used in the radio
  • Charger LED sometimes seems to flash between red and dim red when the batteries are fully charged, rather than turning green.
  • Charger buck converter IC can be damaged if the the PTT is pressed when the transceiver is being changed.
    Note. Most GD-77 users seem to be able to use the radio while its on charge however some users have damaged their chargers doing this.
    Its unclear whether this problem is caused by excessive current consumption because of the additional load placed by the transmission, or whether this problem is caused by RF injection back into the charging input. But when it happens the buck converter IC is physically blown apart.
  • Hissing heard when there is an incoming signal and the volume is turned right down (all firmware versions)
    If the volume is set as low as possible and there is an incoming DMR signal, a sort of hiss / audio noise is heard, even if the audio of the received signal is inaudible.
    Ideally turning the volume completely down should effectively mute the audio completely.
    Note. Thanks to EA3BIL for pointout out, that this is happens when the GD-77 is in the charging cradle and occurs if the GD-77 is charged to more than 8.0V, and is also caused by charger noise from the low quality 12V PSU
    In my case I just checked and my charger had charged the batteries to 8.5V according to the battery voltage on the display.


CPS bugs

The official CPS has many bugs, however I have endeavor to fix all bugs which are in the CPS and not a firmware bug…

If anyone knows of any bugs I have not fixed, please let me know and I will add them to a list and post them here and eventually  (hopefully) fix them in my version.


Update 30th July 2018


It looks increasingly likely that Radioddity are not going to fix any of the firmware issues that have been identified, as there have been several firmware releases since these bugs have been know about by Radioddity,

The least firmware update was over over 2 months ago, and I’ve been told that that Radioddity have been much less active on the Facebook forum in the last couple of months.


Its a shame really, as its a good radio, and could be even better, if they fixed the bugs or let the community fix the bugs – but I don’t think that’s ever going to happen 🙁

53 Responses

  1. p2

    I see you have a display above with call sign AND name. How did you do that?

  2. Roger Clark

    Only works if you use the Digital Contacts as for your DMR ID

    Its a bug / marketing feature that the DMR ID only has the callsign. I asked Radioddity to allow callsign AND name for the DMR ID but they said they won’t change it

  3. PW

    In reference to the RX group set to none and not receiving: it appears this radio behaves unlike all other DMR radios in that you MUST have a RX group to hear anything on a channel unless you have “monitor” on. Every other DMR radio I have used will allow no RX group but will always un-mute and receive on the group listed as the TX Contact for the channel. It’s a bit frustrating since this seems to be the only model radio I’ve ever known to work like this. Not sure if this is a fixable issue?? I’m guessing it’s a firmware thing.