LG G3 Europe (lg-d855)
Before you can use fastboot on this device you need to remove LGs Download mode, which hides the standard fastboot mode. You can do this by zeroing out a partition called 'laf':
adb shell su dd if=/dev/block/platform/msm_sdcc.1/by-name/laf of=/sdcard/laf.img #backup LGs Download mode to the internal SD just in case dd if=/dev/zero of=/dev/block/platform/msm_sdcc.1/by-name/laf #Overwrite laf with zeroes, enabling fastboot exit adb reboot bootloader #reboot directly to fastboot
More detailed instructions for this can be found here
Afterwards, you can boot into fastboot by following these steps:
1. Turn of phone completely 2. Hold Volume Up. 3. Plug in USB-cable while still holding Vol. Up until fastboot pops up
Signing the boot image
pmbootstrap will successfully flash rootfs and kernel, however the device will only boot if you use the
pmbootstrap flasher boot command, as it will otherwise show this error:
ERROR : boot certification verify _________________________________________   Secure booting Error!  Cause : boot certification verify  _________________________________________
The message is shown for 3 seconds, then the screen blacks out and the LED will blink red and blue indefinitely.
This happens because the bootloader on the d855 variant of the LG G3 can not be unlocked and you have to trick the bootloader into thinking your boot image is legitimate.
To do this, you need to first export your boot.img-lg-d855:
mkdir -p /tmp/pmOS_export pmbootstrap export /tmp/pmOS_export
Then we need a tool called Open_Bump, which can sign boot images for our device. (Requires Python 2. Also works for older LG devices?):
git clone https://github.com/CyboLabs/Open_Bump cd Open_Bump python2 open_bump.py "/tmp/pmOS_export/boot.img-lg-d855"
This will create a signed image called
Now first flash System and kernel images using pmbootstrap and then manually flash the signed image over these:
pmbootstrap flasher flash_rootfs pmbootstrap flasher flash_kernel fastboot flash boot /tmp/pmOS_export/boot_bumped.img-lg-d855