WIP as I go along. Ignore

• Latest calibration software is v4.09.00
• F/W v6.02.00.0001 enforces “FCC Narrow Banding” which requires a Software Key to use channels wider than 12.5kHz, which we don't want. Note that the latest f/w available from the Tait groups.io page is v6.02.00.0002 but the filename is truncated, so avoid it. Instead go for V-6.01.00.
• “TM8200 bodies and High-Tier heads must both have matching Firmware versions in order to operate correctly when assembled”
• A TM8100 head seems to work on a TM8200 body
• A “Standard” TM8235 head kind of works on a TM8100 body. The buttons and display work, but the backlight and the status LEDs don't work, and there is some strange flickering behaviour. It's not clear if this could potentially damage something, so might be best avoided.
• A “Standard” TM8235 head seems to work fine on a TM8200 body after being swapped with a High-Tier graphical display head. If they don't, the screen will display “Firmware mismatch” or words to that affect. If you try to upgrade the firmware whilst in this state the programming software will time out. The trick is power off the radio (fully, not via the control head) kick off the firmware download process and then power up the radio after 3 seconds. This might take a couple of goes, but the radio should then start to upgrade the firmware