Unfortunately this doesn't help . I've done a soft reset and a hard reset. In addition I've drained the battery, but the little round light on the back is still on :/.
It may void your phone warranty if you have dev preview installed,since wp 8.1 isn't seeded to carrier/final build. You may flash your phone by nokia recovery tool to downgrade to wp8. Else if you are still on 8 go ahead and ask for replacement, you may have a faulty device mate :smile:
i updated wp8.1 on 25th Apr, everything was good. Today i am facing same issue. at least there should be some solution to turnoff light to use it as a phone.
My 1020 only has this problem AFTER installing the 8.1 dev preview. I'm not really interested in flashing it back to 8.0. Hopefully I won't have to wait for new carrier firmware.
Came back to see if anyone's figured this out, yet. On my second 1020 and, after a month, it's developed the same issue. Win 8.1 Update1 on this one. Previous 1020 is Win 8. Both now have stuck focus lights. REALLY don't want to disassemble the phone.