This is something that should be easy. Really easy. However, it took me a while to find this on the web, and since it did, I’m posting it here too. On XDA, there is a thread about this, intermingled with numerous other threads that say different or sometimes erroneous information.
Back story:
I flashed my LG G4 T-Mobile (H811) phone with a new custom rom I built – OmniRom. Only it didn’t boot. Don’t know why yet, I’m making an engineering build now so I can use ADB to figure that out. As far as I knew, the only ways to get to TWRP were to choose such from your power down menu, or use ADB to reboot into recovery. I thought all was lost, because ADB was not set to on in my custom build, and there was no way to get to TWRP, or so I thought.
I started trying every button combination I could think of.
Found the IMEI screen:
This did lead me to an interesting discovery, if you press Volume down + Volume up + Power, then, when you see the LG logo, release Power (but hold the volumes) wait a second, then press and hold the Power button with the volume buttons, you go into a special IEMI screen that displays a barcode with your IMEI on it.
But I didn’t need that. Quite frankly, you can just open the case and read the sticker to know your IMEI, so this was useless to me, but interesting enough for me to note it here.
After multiple tries, I found the “Factory Reset” screen by holding Volume down + Power, then, when you see the LG logo, release Power (but hold the volume) wait a second, then press and hold the Power button with the volume button. This will take you to the “Factory Reset” screen. I thought that was no good. I wanted to get to the recovery mode.
However, feeling frustrated and hopeless, I chose “yes” for the factory reset. Interestingly, it then flashed the screen, and took me to TWRP!
Believe me, I was very happy!
So, if TWRP is installed properly, then you can get there by entering “Factory Reset” mode, and selecting “yes”. Simply confusing, right? I guess when you say “yes” on stock firmware, it boots stock recovery and performs a factory reset, but since there is no stock recovery, it enters TWRP with a reset flag, which TWRP doesn’t use. Makes sense, I guess. Too bad they just didn’t make it so when you push volume down and the power button during startup that it would just take you to recovery mode like every other Android phone on the market.
Linux – keep it simple.