Quick and dirty –
- Use this cable to connect from back of XPA125B to your computer – if you can’t find this specific model, you need a USB to 3.5mm 3.3V TTL Cable with the FTDI 232RL chipset. The manual says install driver, but with Windows 11, this was not required.
- This zip from Radioddity has all the files you need.
- Install TeraTerm
- As manual says, plug in cable, hold down PA + Band together as you power on.
- Click Update and wait for: “Waiting is connecting…”
- In TeraTerm, select serial and the corresponding com port (check device manager for which port)
- ** In TeraTerm, go to Setup > Serial Port and select 115200 **
- Once it’s waiting to connect, go to File > Transfer > XMODEM > Send ** AND CHECK SMALL CHECKBOX FOR 1K when you select your file **
- Verify – after the logo appears on boot, you should see the the new firmware version and date of its release
You should see it uploading, then after awhile it will reboot itself. If you did not get a reboot or it goes black no display: calm down! Repeat everything above and DO THE 1K thing above. Here’s a great video that helped me: https://www.youtube.com/watch?v=rkM5VIEYqe4.