I'll let you guys keep a tinkering and maybe these FW issues will be solved. (In a perfect world)
DX50 needs soldering so i'll be in the market for a new DAP I can't stand the Iphone 6s Plus sound to Airy, clear though.
I'm confident that iBasso will get these issue fix to only never have a FW problem again.(In a perfect world)
The reason I will stay with iBasso, Astell&Kern have issue with their FW.
So keep trying iBasso