Did you brick your LG G4 H812 smartphone? Here are some tips that could salvage your device

This was successful in my Koodo LG G4 H812

Follow the instructions at https://forum.xda-developers.com/g4/help/lgup-install-kdz-mm-lp-t3249803 (section: TO GO BACK TO LP FROM MM )

Open LGUP on your computer, select "Upgrade", click on FILE PATH and point it towards your LP KDZ. Close LGUP and re-open LGUP. Make sure you select REFURBISH this will do a full wipe, tick BIN file. Press Start. Make cup of tea and be patient 

There is no need to enter download mode! LGUP will do it for you.

The software will take care of all the things automatically and reboot to Android.

Root Telus Rogers Koodo LG G4 H812 by downgrading from Marshmallow to LollyPop

There is  no root available for LG G4 H812 Marshmallow (MM) devices now, but root is available for LollyPop (LP). The strategy here is to downgrade to LP from MM and root the device. You need to disable the OTA updates, since the root will be lost if you upgrade.

1. Download stock KDZ from https://forum.xda-developers.com/g4/general/canadian-guide-complete-source-lg-g4-t3212449
   1. I downloaded "H81210n_00_1204STOCKkdz". All carriers are cross compatible (Bell, Rogers, Telus, Wind)
   2. If you have downloaded 10n kdz, you should download 10n rooted image. I downloaded "H81210nROOTEDrogers.rar"
2. Downgrade from Marshmallow to LP https://forum.xda-developers.com/g4/help/lgup-install-kdz-mm-lp-t3249803
   1. TO GO BACK TO LP FROM MM - Open LGUP on your computer, select "Upgrade", click on FILE PATH and point it towards your LP KDZ. Close LGUP and re-open LGUP. Make sure you select REFURBISH this will do a full wipe, tick BIN file. Press Start. Make cup of tea and be patient 
      
      If you are worried about losing your data after a full wipe, why not use the LG Bridge software to backup and restore.... it works fine!
      YOU WILL LOSE ROOT!
      There is no need to enter download mode! LGUP will do it for you.
3. Install ROOT https://www.reddit.com/r/lgg4/comments/3ir4zn/guide_how_to_root_all_versions/
1. Use dd if=/data/media/0/rootedsystem.img bs=8192 seek=65536 count=548352 of=/dev/block/mmcblk0 for H812 (all Canadian carriers LG G4)
4. Install Xposed using https://forum.xda-developers.com/g4/themes-apps/guide-installing-xposed-locked-t3181593
1. Follow instructions below worked for me
2. Download FlashFire version 0.24, and xposed-v87-sdk22-arm64.zip
3. Set your date of phone back to June 2015 .
4. v0.24 has only one option (Auto-mount), which I left unchecked.
5. 20 minutes of blank screen, then some flashfire text and a reboot, it optimized apps, and then finished normally.
6. Install the xposed installer apk (XposedInstaller_3.0_alpha4.apk) and it reports v87 is active 

Install TWRP custom recovery on Koodo LG G3 D852 on Lollipop 5.0.1

1. Install (D852) LG G3 AutoRec-Lollipop
2. Install Reboot
3. Open the app and grant root access using SuperSU
4. Click the option to install TWRP and TWRP will be successfully installed.
5. Verify TWRP installation by clicking Reboot app and reboot to recovery.
6. The phone will reboot to TWRP recovery

Installing CyanogenMod 7 (mil version) ROM on Koodo LG optimus One Android phone (P500h)

Root the phone before doing this.

Download cyanogen_thunderg-ota-eng.mil-6.5.4.zip into your microSD card. CyanogenMod 7 ROM is based on Gingerbread. Install ROM Manager on your phone. Open ROM Manager and select Install ROM from SD card. Now browse to the downloaded cyanogen zip and tap it.

In the menu, check backup existing ROM (if you want to back up the current OS, highly recommended). Check the options to wipe data/cache and dalvik cache. Now Tap OK. The phone will restart and backup the files and then proceed to CM7 installation.

The phone will automatically restart after the installation (takes about 5-10 min). You will see a brand new OS on your phone. Go to settings and add your google account to synchronize contacts, mails etc.

If you want any other google applications which are not already installed with CyanogenMod 7, follow these instructions.

The same procedure can be used for installing any other android ROMs.

ALL CREDITS TO ORIGINAL DEVELOPERS.

Install google apps on your new Android OS.

If you want any other google applications which are not already installed with your current Android ROM (like CyanogenMod 7), download apps-addon.zip. If you don't have it already, install ROM Manager on your phone. Open ROM Manager and select Install ROM from SD card. Now browse to the downloaded zip file and tap it.

In the menu, check backup existing ROM (if you want to back up the current OS, not required in this case for installing google apps). Uncheck the options to wipe data/cache and dalvik cache. Now Tap OK. The phone will restart and backup the files and then proceed to gapps installation.

ALL CREDITS TO ORIGINAL DEVELOPERS.

Rooting Koodo LG optimus One Android phone (P500h)

This procedure will work for LG optimus One Android phone from Koodo (P500h). This may work for other LG Optimus One phones as well, but I have not tested it.

Do not use z4root to root this phone (many people suggested to use this, but didn't work for me at all). The process takes forever without any result.

Download GingerBreak-v1.20.apk (google it, I am sure you will find it). In the application settings, allow installation of non-market applications and enable "USB debugging" in Application settings>Development. Once you install the apk, you will be able to do a "Permanent root" without any fuss.

Please leave a comment, if you have success with any other methods.

If you want to go ahead and install a new ROM (for eg cyanogenMOD 7) instructions are here.

File explorer for LG Optimus one (Android)

What I mean by best file explorer for Android? It should easily navigate to your microSD card. It should be able to access your (home) network contents. This is especially important because this allows you to get rid of the usb cable.

The file explorer which I am using for these purposes is ES file explorer. It is free and you can configure (map) the network drives. Once it is done, just tap the LAN and all the mapped drives will get listed. It is as easy to use as Windows 7 Homegroup. You can play music/movie files in your phone like this. It allows copy/paste from network computer to micro SD card. Really useful software.

Disassembling the LG P500 Optimus One

All owners of LG P500 Optimus one should see this.

Media player for LG Optimus One

The stock media player in Android is just ok. It will not play all video files. If the resolution of the avi file is higher (resolution more than 640x360), it will give an error message "resolution not supported".

However, you can freely download Moboplayer. This is the best player I have tested. They say that it can technically play any file played by VLC media player, since they use the same codecs (FFDshow). Anyways, Moboplayer was able to play the files rejected by stock player. There was no "resolution not supported" messages anymore.

Note: Make sure your video file does not have AC3 audio. mp3 and AAC audio work fine.