This post is mirrored from Facebook. All credit goes to Kevin Omura
Why did I brick my UV-K5???
The simple answer is, because of not knowing which version of radio you have or ignoring all the warnings. Seems like a simple answer but is it really?
I own several UV-K5 radios as well as some UV-K1 radios and so it seems like a good idea to do a sort of guide as to how to identify them.
Perhaps the simplest way is to just take the battery off and look at the label on the back of the radio. On there you should find the model number and possibly a V2 or V3 designation. On the original V1 radios there is no version number.
Why this is important. Quansheng has changed the microprocessor on these radios at least three times during their production run.
The first radios have the DP32G030 a 32-bit Arm Cortex-M0+ microcontroller running at up to 48MHz and with 64kb of internal flash memory. (this is important to note)
https://www.nationstech.com/uploads/packs/1662538843129211.pdf
Then around the end of 2025 it was reported that a UV-K5 V2 radio had shipped. It has a different microcontroller the PY32F030 32-bit ARM® Cortex® - M0+ CPU running at 48MHz and also with 64kb of internal flash memory. (I do not own one of these yet)
https://download.py32.org/Datasheet/en/PY32F030_Datasheet_V1.8.pdf
Finally at the beginning of 2026 Quansheng shipped yet another variation of the UV-K5. This time a V3 version which had a PY32F071 ARM® 32-bit Cortex®-M0+ CPU running at 72MHz and with up to 128kb of internal flash memory.
https://download.py32.org/Datasheet/en/PY32F071_Datasheet_Rev0.7_EN.pdf
So, what is the important thing to note here? It is how much internal flash memory these MCUs have and why some people have bricked their radios.
This relates specifically to the latest versions of Armel's really great F4HWN V4.3.2 Fusion firmware upgrade for the UV-K5 V3 and UV-K1. If you fail to heed his warnings on his page or any of the other warnings out there you WILL BRICK your UV-K5 V1/V2 radios.
Why? Because V4.3.2 Fusion firmware requires 79kb of flash memory and those earlier radios only have 64kb. The new V3 radios have the upgraded MCU which has 128kb of internal flash memory and so it is large enough to store his firmware as well as Ari's Fusion + firmware which can require even more memory approaching the 128kb limit of the latest chip.
So that brings us to the final problem and that is mainly with the UV-K5. It has been reported that some radios that have shipped that were supposed to be V3 radios actually have V2 boards in them. *Note that I do not own one of these radios yet. And this is a big problem since trying to flash one of these radios with Fusion will brick it since the flash memory is not large enough.
IMHO that means unless you are 100% certain that your radio really is a V3 I personally would not install any of the new firmware which requires the larger flash memory. Therefore, I think it is a lot safer to experiment with the UV-K1.
Is there another way to determine if you have a V3 UV-K5?
Maybe, I posted some photos of three of my UV-K5 radios with notes on each photo as to which version it was. There is a photo from the UV-K5 V1 which has no designation, a UV-K5 ( 8 ) and my UV-K5 V3 which I have tested with F4HWN V4.3.2 as well as Ari's Fusion + firmware. I can't 100% guarantee that your radio is or is not a V3 but if it has the version code R51-V2.1 it should be. This radio also had OEM firmware version 7.0.11.
If you did brick your radio, Armel has posted a very good tutorial on how to go about unbricking it. It does require some surgery and extra pieces of hardware.
https://www.youtube.com/watch?v=4cWtYH_bpro
