[G4 Q&A, Help & Troubleshooting] benni_g4:
I followed your instructions and selected the flash folder containing the TWRP preview image file. Then, I need to choose the partitions I want to flash. My TWRP preview image is displayed there, as shown in the picture.

[IMG="Select flash partition"]https://xdaforums.com/attachment.php?attachmentid=5037921&stc=1&d=1591802084[/IMG]

I don't understand, how I can choose the BOOT partition here. I thought, I could simply type in the string "BOOT" in the "Target Partition" column. But after pressing FLASH, two error dialogs appear.

This is the according log output:

2020-06-10 17:25:06: F_FLASHPART: started
2020-06-10 17:25:17: F_FLASHPART: IMGDIR=/home/benjamin/Downloads/twrp_flash
2020-06-10 17:25:17: F_CHKDEVCON: started
LGLAF.py: DEBUG: product id in CR list: >LG_new<
LGLAF.py: DEBUG: Device is: 633a, LG_new. Enabling Challenge/Response!
LGLAF.py: DEBUG: Final CR detection: None / 1
LGLAF.py: DEBUG: Using endpoints 83 (IN), 02 (OUT)
LGLAF.py: DEBUG: Using Protocol version: 0x1000001
LGLAF.py: DEBUG: CR detection: 1
LGLAF.py: DEBUG: Hello done, proceeding with commands
LGLAF.py: DEBUG: Challenge: b'1a63780b'
LGLAF.py: DEBUG: Response: b'764940f602e3805cb7098e6d602cbaed'
LGLAF.py: DEBUG: KILO METR Response -> Header: b'4b494c4f4d455452000000000200000000000000000000002f5d0000b4b6b3b0', Body: b''
LGLAF.py: DEBUG: Header: b'EXEC' b'\0\0\0\0' b'\0\0\0\0' b'\0\0\0\0' b'\0\0\0\0' b'\0\0\0\0' b'\x1fW\0\0' b'\xba\xa7\xba\xbc'
2020-06-10 17:25:17: F_CHKDEVCON: Device seems to be connected!
2020-06-10 17:25:17: RET: 0
2020-06-10 17:25:17: F_USUVARVALID: started
2020-06-10 17:25:17: F_FLASHPART: will display all files (USUOVERRIDE=FALSE)
2020-06-10 17:25:17: F_FLASHPART: image files: twrp-3.3.1-PREVIEW-213_g4_P.img
2020-06-10 17:25:17: F_FLASHPART: created yad list: true
twrp-3.3.1-PREVIEW-213_g4_P.img
twrp-3.3.1-PREVIEW-213_g4_P
unknown-type
2
2020-06-10 17:25:30: F_FLASHPART BTNRET: 0
2020-06-10 17:25:30: choosen partitions: twrp-3.3.1-PREVIEW-213_g4_P.img:BOOT:unknown-type:2 -> 1
2020-06-10 17:25:30: sorted partitions: twrp-3.3.1-PREVIEW-213_g4_P.img:BOOT -> 1
2020-06-10 17:25:30: F_VERIFYDARB: started with /home/benjamin/Downloads/twrp_flash
2020-06-10 17:25:30: F_CDARB: started
2020-06-10 17:25:31: F_CDARB: ARB partition seems to be: sbl1
2020-06-10 17:25:32: F_CDARB: DEVARB=0, DEVARBEMPTY=0
2020-06-10 17:25:32: F_CDARB: ended
2020-06-10 17:25:32: F_VERIFYDARB: KARB: , DARB: 0:0,
CHKMRES: unknown VS. unknown
2020-06-10 17:25:32: F_ERR: started
2020-06-10 17:25:32: ERROR: 3 occurred in F_VERIFYDARB (expected 0, got 3)
2020-06-10 17:25:32: F_MSGE: started
2020-06-10 17:25:34: ERROR:
ERROR!

Device ARB or file-based ARB cannot be checked! ABORTED!!
2020-06-10 17:25:34: 0
2020-06-10 17:25:34: F_EXIT: started
2020-06-10 17:25:34: EXIT: F_VERIFYDARB->F_ERR with code 4
2020-06-10 17:25:34: F_ERR: started
2020-06-10 17:25:34: ERROR: 3 occurred in F_FLASHPART (expected 0, got 3)
2020-06-10 17:25:34: F_MSGE: started
2020-06-10 17:25:35: ERROR: Aborted on user check verification (2020-06-10 17:25:32: ERROR: 3 occurred in F_VERIFYDARB (expected 0, got 3)
0
2020-06-10 17:25:34: EXIT: F_VERIFYDARB->F_ERR with code 4)
2020-06-10 17:25:35: 0
2020-06-10 17:25:35: F_EXIT: started
2020-06-10 17:25:35: EXIT: F_FLASHPART->F_ERR with code 4
2020-06-10 17:25:37: F_ADVMENU: started with LG-H815
2020-06-10 17:25:37: F_ADVMENU: main YAD_PID is 7508
2020-06-10 17:25:38: CR setting: Auto =
2020-06-10 17:25:38: getlog script started

Am I doing something wrong, or is this related to something else?