Sonoff RF Gateway Firmware Rollback

Hi,
I flashed my Sonoff RF Gateway with Tasmota and then upgraded the Sonoff with OMG.

Does OMG have a method of upgrading to a new version of OMG or upgrade back to Tasmota?

I found that after I have upgraded to OMG, when trying to flash again, the light on the sonoff RF Gateway doesnt turn on, is that normal?

Regards,
Alpha