I have never seen any firmware for the Mini60 in the net. The only firmware i am aware of is the one for Sark100. The firmware in the Mini60 is basically the same with Sark100 with a few minor changes. I do not recommend to flash a Sark100 firmware in a Mini60. It could be useless after such an attempt. FYI, here you find the firmware and much more regarding Sark100.