I have already posted this message in another post ([FIX] NO Recovery mode, No download mode, after OTA rooted on LG G2 )
I have a smartphone lg g2 guarantee europe. I tried to enter the root "ioroot25" and with the program "Root Checker Basic" I got confirmation that the operation of the root is successful. After the application "Flashify" I tried to flash the recovery TWRP (version 184.108.40.206), after removing it I flashed the recovery, and I clicked Reboot Now.
After that the device will restart and with the logo Lg there are written:
"Boot certification verity
secure booting error
CAUSES: Boot certification verity. "
In an attempt to restore the original firmware of my Lg G2 I found that my device does not go into Download Mode.
I think I messed up my lg g2, I tried to follow your guide with Ubuntu software.
I connected my device to the PC, I opened the terminal resistor Ubuntu (CTRL + ALT + T) and I inserted the following code:
ls /dev/sd *
/ dev / sda / dev / sda1 / dev / sda2 / dev / sda5
Can you help me.