Neil
I had the same problem recently.
You probably have a newer radio with another CPU, see behind the battery if there is small “V2”, next to the UV-K5(8) on the label.
All the older firmwares don’t work on that CPU.
I used a firmware by F4WHN ( a derivative of the egzumer firmware), ported to the V2 model , and that works great.
Here is a video about it (in French, but you can add English subtitles):
https://www.youtube.com/watch?v=XfJHgWU7GKQ
I used the “Bandscope” variant, which lacks the FM broadcast band.
The “Broadcast” variant then lacks the interesting spectrum display, so you have to make a choice.
I don’t know if and when the IJV firmware will become available for V2. If someone knows more, please report here.
PS1 : there is a nice Wiki about all the features of the F4WHN firmware:
https://github.com/armel/uv-k5-firmware-custom/wiki
PS2 : you will need another python script to program the rig with CHIRP, that can be found here:
https://github.com/armel/uv-k5-chirp-driver
PS3 : I now see there is also a “Basic” variant, which has bandscope AND FM band, but then lacks some other (less important) functions.
73,
Luc - ON7DQ