I would like to completely wipe my phone and re-flash. Of course I am already rooted and running a custom ROM. My question is, is it safe to boot into TWRP and do a nandroid backup to my USB-Drive (OTG). Then do a system reset and ALSO FORMAT DATA so all is gone. Then can I flash from my USB by mounting it in TWRP and flash my ROM from the USB drive since the internal memory will be wiped clean.
Thanks for info.