Need help in unbricking soft bricked LG G2 LS980

I recently purchased **LG G2 LS980** (locked on Sprint network in USA) in India and unlocked it to work in India. The build number of the software that came with phone was **LS980ZV7**. The phone kept downloading OTA updates (which I could never stop) and I kept installing them. The software version updated from ZV7 to ZV8 to ZVA. After ZVA, the phone downloaded ZVA to ZVC update (611 MB) several times, installed but never updated the software version. In every update, the phone rebooted, optimized apps and booted normally. One day, I installed TWRP (Team Win Recovery Project) on my phone. The phone again downloaded an ZVA to ZVC OTA update . I went on to install the OTA update. The phone rebooted into TWRP and never booted back into normal mode since then. In an effort to restore the phone, I did what ever possible to restore the phone. I even did the hard reset of the phone. But the phone still boots into TWRP. Now, in a way, the phone is "soft bricked". And the only option (I may be wrong) seems to flash the phone with a custom ROM. Any help please. Thanks in advance