I have been told that LG phones are painful to get into fastboot but i didn't realize it was impossible. I have the LG K8 2017 (LG-M200n) and I have tried all: #adb devices shows the device is listed, then #adb reboot bootloader does nothing but reboot my usb connected phone. of course fastboot devices shows nothing. I even tried the recommendations to enter fastboot by power down phone, vol down key and connect usb, but phone turns on normal, no fastboot. any help?
I found the answer. It is not possible because of the hardware itself. LG sucks really. Here is the info from their developers site which explains all the difficulty (LG K8 not listed below :():
"The following devices support unlocking the bootloader:
• LG V50: LMV500EM for the European market
• LG V40: LMV405EBW for the European market
• LG G7: LMG710EM for the European market
• LG V30: H930 and H930G for the European market
• LG G6: US997.USA for the U.S. open market
• LG G6: H870 for the European market
• LG V20: US996.USA for the U.S. open market
• LG V10: H960A for the European market and Android M (Except France)
• LG G5 SE: H840 for the European market
• LG G5: RS988.USA for the U.S. open market
• LG G5: H850 for the European market
• LG G4: H815 for the European market
Unlocking the Bootloader is only supported on selected devices."
The lesson learned here: verify the capabilities of the phone you want to buy before wasting your money.