The LG Optimus F7 (LG870) for BOOST MOBILE USA has been available for a while.
Here is the Official Stock Firmware / Rom for Boost Mobile LG Optimus F7 (LG870) straight from LG Server.
Download BOOST MOBILE LG Optimus F7 (LG870) Stock Rom / Firmware Revision ‘LG870ZV5’.
Direct Download Link:
Please notes that the LG870ZV4 is no longer available for download from LG.
It is a .cab file about 1.1GB in size, You may need to use latest LG Flash Tool to flash this stock rom onto your LG Optimus F7 (LG870) cell phone. Go Xda forum to find out instructions on how to convert LG cab firmware to KDZ format.
wish this helps.