[LG V20 Guides, News, & Discussion] xdav20:
New Order

Original Order

Downgrade to 10c>Install Recovery>Install Custom Kernel>Install SU, Upgrade Firmware 10f/10g.

Technical Discussions

The most critical technical issue with original order is, when the firmware is upgraded the ramdisk (and kernel modules that are not replaced by the custom kernel) of the boot partition remains at 10C version and only the kernel part is upgraded by a custom version. To avoid any unpredictable behaviours with the firmware, it is a wise decision to match the ramdisk version to the firmware version. Look at all the files on root of your device, many of them, if not all, are being copied from ramdisk to the device on every device start. The ramdisk contains files with hundreds, if not thousands, of settings that are executed and applied during the boot process. For instance, the 10f or 10g may have new settings that were corrected the previously wrong parameters or to improved them.

New Order

Downgrade to 10c>Install Recovery>Upgrade Firmware to 10f/10g/Install Custom Kernel>Install SU

Technical Discussions

Not a single boot to the system (Android) after the firmware downgrade to 10c. After recovery installed you will never need access to a Windows machine, ever again, because you can have a 100% pure stock version of 10f or 10g ready to be restored from TWRP at any given time, unlike the original order where the firmware always has to be downgraded first. All future firmware upgrades then can be installed by kdzwriter over the 100% stock with far less work and technical issues.

As mentioned in above, everything, but what custom kernels replace, in boot partition will match firmware's version.

Instructions:

1. Copy 10f or 10g .kdz file to the root of your external sd card and rename it to lg.kdz. Typing in TWRP is not easy, you do want to keep the name short.

2. Follow the original method to install the TWRP recovery, boot to recovery, cancel password, swipe to allow modifications, factory reset, format data, reboot the recovery as is recommended after data partition is wiped

3. Install kdzwriter using these instructions without a pc

4. From TWRP's terminal run the following command

kdzwriter -a -k /external_sd/lg.kdz

wait until the process is completed.

5. Backup your firmware to your external sd card. This is your only chance to have a 100% stock, not to use but to upgrade future firmwares or to start clean again if you don't want to do the tedious work of installing TWRP again. Before booting to this version, a custom kernel must be installed at minimum.

6. Install your choice of kernel, followed by the latest SU of your choice

7. Boot to system to complete the process.

Notes:

I backed up a fully setup 10f firmware, installed by the new order, and restored it on to my 2nd H990DS right after I installed and wiped everything in TWRP without any issues. If you own more than one too, don't forget to rename your device in About menu to avoid Bluetooth and Wifi naming conflicts.

Update-01:

When I tried to use the backed up 10f stock that was flashed by -a -k flags I started having problems to flash other kdz versions, not the result I expected. I'm updating this post to let you know, your lifeline is with the backed up 10c stock per instructions in the OP.