you are not alone dude. i had the same issue since sunday and i have spent almost 46 hours already trying to restore my LG G2 F320S korean model.
i followed that instruction in linux, everything went well but then I ended up with a phone not going past the LG logo. the screen no longer dims like how it used to with the secure boot fail error. again, it stucked at the LG logo and thats it.
pressing the 3 buttons though for 5 seconds shows a white screen with 3 options and a bar code under.
but all of these options will just take me back to the LG logo.
I went to a phone technician today, and they said the doing a JTAG fix is the only way to resolve the problem because after trying to fix it with linux, it is no longer identified by my PC.
what are your solutions so far?
anyways before this issue came up, i tried to flash TWRP using flashify, it failed. then went back up. tried to update the OS via OTA then thats it.
i home someone could help us out.
HI Sneaky elephant........bro I am having the same problem with my lg g2(hard bricked) that its not recognised by Ubuntu...it just shows hssusb-hulk.....no partitions to mount.............
in ur next reply u said that issue solve.....
kindly tell me too that how ur issue resolved...........thanks......