When I've upgraded to v7 to check Bluetooth bug (which hasn't been fixed) I've never updated to v6 1st. I do it this way...download twrp 2.8 & v7. Boot to recovery (twrp 2.5) install twrp 2.8, now do not reboot, pull the battery out (10seconds) , put battery back in & holding down power button & vol down go back to recovery & you should have twrp 2.8 installed. Do full wipes & then install v7. As always do a back up 1st via twrp.
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