Good tip, another 20 MB saved, now got to 135 MB free on C.
C:\Private\102072c4\Reserved is a FOTA file, dunno if it recreates itself, so I just moved it to E (or F would do). Then I can move back if get OTA update probs.
Search '20 MB big "reserved file" in Private\102072c4' in forum here..
It says, ""delete it then dial up *#0000# and you'll have it back if you miss it that much...so the answer to your question is yes, you can delete it""
The file holds firmware info. it gets back in place once u dial *#0000#... no worry u can delete it!