To help you programme and update the firmware for the popular dual band digital Retevis RT82, please watch the videos below which have been produced by Barry 2E0DTS.
Here is a review of the RT82 by Paul M0RNP: -
When I first used DMR, I had a Retevis RT8 and was impressed with the build quality and the range of accessories and have not been disappointed with the RT82.
What I like about the RT82 are the ergonomics, the radio is well balanced, easy to use in one hand and being able to set the function of the buttons. The battery life is good and the receive audio is very good for the size of speaker. The radio is built to withstand being dropped and to have some knocks but I do not recommend you try it out. The only things that can be a problem are if you are using the menu, when the radio receives a signal it will go back to the opening screen, when you are in scan mode the LED flashes and is ultra-bright, you can turn it off but are not able to reduce its brightness, this can be annoying and these are the only things I don't like about the radio.
Accessories are well built and work well.
There are many users in the Folkestone area with this radio, a local code plug is available for users on request.