Please read the followed FAQ for help: 


M11 Plus LTD: https://forum.fiio.com/note/showNoteContent.do?id=202107010956367510284


M6: https://www.fiio.com/newsinfo/477750.html


M7:https://www.fiio.com/newsinfo/477747.html


M9:https://www.fiio.com/newsinfo/477746.html


M11/M11PRO:https://www.fiio.com/newsinfo/477748.html


M15: https://www.fiio.com/newsinfo/477751.html


How to wipe the cache & data in Recovery mode on X5 3rd gen/X7/X7MKII:

https://forum.fiio.com/note/showNoteContent.do?id=202107010951359479798&tid=21