Voltage issue with USB port on PC made USB data pin on phone to stop working but charged just fine. Not a problem with wireless adb but while flashing new rom, I mistakenly deleted everything on the phone including the rom zip. I tried everything to get the rom zip on the phone from usb-otb to different cables to battery drains but nothing worked.
Having given up, I got a cheap phone. While m7 sat in the closet. Recently, I was cleaning my room and spotted my m7 abandoned it didn't feel right. Decided to get a new m7 usb port and replace the faulty part. Hardest part was taking out the back cover off m7. Replaced the usb and it worked! Finally back from dead.
Turns out m7 is really hard to get the back off without damaging the cover so I got $11 back cover replacement. Youtube video on replacing just the usb without removing all the other parts with help of tweezers helped lots. Shipping to Canada is a strange paradox, I want product to arrive fast however if I pay over ~$30USD (~$40CAD) for 2 day fedex shipping, I get charged extra $15CAD by fedex for faster customs passage. And regular delivery takes minimum 1 month and costs ~$15USD (~$20CAD). ifixit needs to update shipping speed and costs to Canada. And oh I got rid of the faulty usb ports on the PC as well, took less than 3 minutes and a Phillips screwdriver.