Its been a week or so since i have bought one plus one from amazon.in . So am now using multirom with that. I have three roms based on android 5.0.2 running through Multirom. I wanted to go back to stock so i flashed Stock Rooted 4.4.4 XNPH30O
zip via multirom recovery . and now there is proximity issues .Screen is black during the call. I see this is common with all one plus one devices. Googled about that and got a suggestion to flash the modem for the corresponding build number. I did. but again the same issue.