I installed this firmware from your earlier post, and in my case it looks like it is ok. It all uploaded correctly using the firmware updater programme that was in your post then I opened the TF GUI (in Siya’s later post) and it connects and reads ok. So I’m not sure how it can damage some boards - unless some of hardware is different.
I connected to the TFmini with a custom cable I made from the one that came with the TFmini and using a FTDI232 adaptor I had lying around. (The custom cable looks a lot like the one you made)
For info I bought my unit from the 3DXR.co.uk website about a week ago.
I’ll post up some photos/screenshots shortly.