Shelly TRV custom firmware?

I recently received my TRV, pretty impressed by the device so far!

I find the UX of the physical button a bit inconvenient: long-pressing and holding the up/down buttons to set the target temperature. I would much prefer to be able to toggle between 'high' and 'low' settings (with some preconfigured values for 'high' and 'low') with a simple short press.

I assume this is not possible with the official firmware, which is fine: one of the reasons I chose Shelly is because the company seems to be friendly towards custom firmware (e.g. tasmota).

Is there any information available about custom/opensource firmware options for the TRV yet?