You cannot use Baofeng CPS anymore. Download and install the OpenGD77 Codeplug Programmer. This software is vastly superior to the stock Baofeng CPS.
(Same as above: PTT + Monitor button while powering on). baofeng dm1702 firmware update
Run the loader. It will detect your radio in DFU mode. Select the OpenGD77 firmware file (for the DM1702, not the GD-77). Click "Write to Flash." The loader will first erase the stock firmware, then write the new one. You cannot use Baofeng CPS anymore
The Baofeng DM1702 is a popular choice for amateur radio operators who want a dual-band, dual-mode (Analog and DMR) handheld transceiver without breaking the bank. However, like many Chinese radios, the stock firmware shipped from the factory is often a "minimum viable product." To unlock the true potential of your DM1702—or simply to fix persistent bugs—performing a Baofeng DM1702 firmware update is essential. (Same as above: PTT + Monitor button while powering on)
Go to the official OpenGD77 site and download the latest OpenGD77_Loader.exe .
Click "Open File" and select your downloaded .bin firmware file. Click "Upgrade." The progress bar will move from 0% to 100%. Do not touch the cable or the radio. This takes 2-3 minutes.
Turn off the DM1702. Connect the programming cable to the radio’s side port (the same port used for programming channels). Insert the USB end into your PC.