1. Download and install QMK Toolbox:
https://github.com/qmk/qmk_toolbox/releases/tag/0.0.8
2. Download and install the firmware that works with VIA Configurator:
https://rama.works/s/rama_m60_a_default.hex
3. Run QMK Toolbox.
Hold down escape when plugging the M60-A into the computer. (only required if not already in DFU mode)
QMK Toolbox should detect a "DFU device" connected and show a message "*** DFU device connected: ATmega32U4 -- 0x03EB:0x2FF4"
Click the "Open" button at the top of the window, browse to where you saved "rama_m60_a_default.hex "
Click the "Flash" button. More messages should appear with "Success".
You don't need to use QMK Toolbox again for changing keymaps.
Here's a screenshot of the new firmware installed on the M60-A:
4. Test the M60-A
You might like to try this useful tool: https://elitekeyboards.com/switchhitter.php
At this point, it should be working with the default layout.
5. Download and install VIA Configurator:
https://github.com/olivia/via-config/releases/latest
This should detect the M60-A and the window should look like this:
VIA Configurator only requires firmware be installed once, thereafter, all changes to the keymaps are programmed instantly!