OpenGD77 on the Baofeng DM-1801 and RD-5R: bring your radio to life

The Baofeng DM-1801 and RD-5R are the most affordable DMR radios built on the Radioddity GD-77 hardware platform. Their stock firmware is mediocre: the CPS is clumsy, the feature set is thin, and updates stopped long ago. OpenGD77 is an open alternative firmware that completely changes the picture: proper hotspot operation, advanced receive features, a built-in DMR ID database, and private-call support. Installing it isn't hard — the key is not skipping the backup step.

Which radios OpenGD77 supports

The firmware is written for the NXP MK22 + AT1846S + HR-C6000 chipset. The following radios run on this platform:

• Radioddity GD-77 and GD-77S
• Baofeng DM-1801 and DM-1801A (hardware revision 1 only)
• Baofeng RD-5R

Radios on other platforms — for example the TYT MD-UV380 (STM32F405) or the Baofeng DM-1701 — are also supported by OpenGD77, but that's a separate firmware branch with its own installer. Don't mix them up: flashing the "wrong" image turns the radio into a brick.

What you'll need

• A Windows PC (Mac/Linux can work too, but the Firmware Loader is officially for Windows).
• An original USB programming cable for the GD-77/DM-1801 (the two-wire audio plug, 2.5 + 3.5 mm). Cheap clones often don't work.
• OpenGD77 CPS installed — download it from opengd77.com (Downloads → Releases section).
• The firmware archive of the same release as the CPS (the .bin file inside the archive — don't unpack it).

Step 1. Backup — mandatory, no exceptions

Before doing anything else, make a full backup of the radio. If something goes wrong, only these files can restore the original state.

1. Connect the radio to the PC with a programming cable and turn it on.
2. Open OpenGD77 CPS (still on the stock firmware at this step — that's fine, CPS can read it too).
3. Go to the Extras → OpenGD77 Support menu.
4. Run in sequence:
   • Backup EEPROM — settings and codeplug;
   • Backup Flash — voice prompts and additional data;
   • Backup MCU ROM — the bootloader (critical!).
5. Save all three files somewhere safe. Label them: model, date, serial number.

Step 2. Entering bootloader mode

To receive the firmware, the radio switches into a special bootloader mode. The procedure is the same for the GD-77, DM-1801 and RD-5R:

1. Turn the radio off.
2. Press and hold both side buttons at the same time — SK1 (upper) and SK2 (lower).
3. While still holding the buttons, press the power button and turn the radio on.
4. Release the buttons after 1–2 seconds.

Sign of success: the green LED is lit and the screen stays black. If the normal boot screen appeared, try again, holding the buttons longer.

Step 3. Flashing the firmware via Firmware Loader

1. In OpenGD77 CPS, open the Extras → Firmware Loader menu.
2. In the dropdown, select your model: DM-1801 or RD-5R (not GD-77!).
3. Click Select firmware file and point it to the downloaded firmware .bin file — don't unpack the archive, CPS can read the zip directly.
4. Make sure the radio is in bootloader mode (green LED), then click Flash firmware.
5. Wait for the progress bar to finish. CPS will report success.
6. The radio will reboot on its own — you'll see the OpenGD77 startup screen.

Step 4. Initial setup after flashing

The radio has started with OpenGD77, but the codeplug is empty. You need to:

1. Enter your DMR ID and callsign. In CPS: Extras → Options → Radio Info. Without this, others will just see a number instead of your callsign.
2. Load the DMR ID database (optional). Extras → DMR ID → Download. With the database, the radio shows callers' callsigns on the screen.
3. Load a codeplug for your network and hotspot. For DMRhub, there's a ready-made file in the /contacts section.

DM-1801 and RD-5R specifics under OpenGD77

The DM-1801 is a dual-band radio (VHF 144–146 MHz and UHF 430–440 MHz in Russia), with a full display and extra side buttons. It works well as your main radio for a hotspot at home and on the go.

The RD-5R has a compact form factor, compatible with Kenwood accessories (the 2-pin K1 connector). Two bands, but a smaller display. A good portable radio for field use.

Both models support all of OpenGD77's key features: digital monitor, zone scanning, private calls, analog mode, voice prompts. Simultaneous reception of both time slots on a hotspot works correctly.

Reverting to factory firmware

If for some reason you need to return to stock, it's possible as long as you've kept the MCU ROM, EEPROM and Flash backups. In CPS: Extras → OpenGD77 Support → Restore, then choose the backup file you need. The procedure is the same as flashing: put the radio in bootloader mode, then restore.

Without the MCU ROM backups, the radio can only be recovered using a special patched bootloader from opengd77.com — a more complex procedure that requires knowing memory addresses.