[LG V30 Guides, News, & Discussion] zacox123:
This thread only introduce hardware methods to enter specific modes, however, if possible, use software method like advanced reboot, adb reboot, magisk reboot, etc. instead for stable entries.

Force reboot: hold both volume- and power keys for 8 seconds (maybe reboot at the 9th second, so hold until the screen changes). This can quit any other mode. Somebody says if you can count time accurately, you can just shutdown the phone instead of rebooting, but I have never succeeded:(

Normal boot: when your phone is off, hold power key until your phone vibrates (if your phone can boot to system).

Safe mode: during normal booting, when you see the dynamic animation of LG (not static monochromatic logos), hold volume- key until the phone vibrates (you can start holding it even earlier, but make sure holding it until you really enter the safe mode). In this mode, only system apps, default settings and basic functions are enabled. Any reboot quits this mode.

Recovery (stock for master reset or custom twrp): hold volume- and power keys until the initial boot screen of "LG V30" with "powered by Android" displays. (If you have unlocked the bootloader, this screen would display twice, but only the first time is what we are talking about.) Immediately release the power key and hold it again (in other words, pause holding the power button for less than 1 second). Then after the screen changes, release all keys and do further steps according to the instructions displayed.

LG download mode: shutdown your phone first. Hold volume+ key and connect the phone to a working computer via USB. Then the phone should boot to download mode.

Fastboot/Bootloader (if any): similar like the download mode, but use volume- instead of +. However some firmwares may miss this mode. If it works, it should boot to the fastboot interface immediately and you can power off the phone there.

Information screen (I don't know what it's called exactly): shutdown your phone first. Hold all the three of volume+, volume- and power keys, and this will lead you to a screen listing MEID, IMEI and S/N of your phone with corresponding barcodes.

Qualcomm 9008/EDL/QDLoader mode (sometimes even called Qualcomm download mode, but not Android download mode) (mentioned in One way to force shutdown your phone, try this if other modes do not work): connect your phone to a working computer via USB. Hold volume- and power key, around the moment your phone force reboots press volume+ for multiple times (with holding other keys). In device manager on the computer, see if a device named something with "Q" like QUSB_BULK (no proper driver installed) or Qualcomm EDL HS-USB 9008 (proper driver installed) other than anything containing "Android" or "ADB", the phone enters the 9008 mode. If not, unplug the cable and try it again. This can turn off the screen. If you find difficulty to perform it, you can also try other more general methods like test points shortening (see test points lg v30 plus for 9008 mode) or engineering cable (not tested yet).

Yet there is no way to shutdown the phone directly with simple key combination, but you can refer One way to force shutdown your phone to make it if you cannot use regular methods to shut your phone down.

If anything missing, please reply to let me know:)