undoing the firmware update

[patl1]

I want to undue the firmware update I performed with this process back to original ewelink compatible firmware. The reason is that Smartthings no longer works with the revised firmware that used the DTH to allow connection and I cant find an edge driver that will work. a While ago, ewelink and smartthings decided to play nice and I am able to link directly from ST to Ewelink now so I don't need the extra interface. Anyone know how to undo the firmware change back to original or current eweking firmware on the sonoff basic wifi switch?