[G2 Q&A, Help & Troubleshooting] Pthagonal:
Update:

Somehow, the phone came back, sort of (battery low?!), and I was able to see all partitions again.

So I tried fixing the problem by copying boot.img and laf.img to the respective partitions ... I guess you shouldn't try these things at 1:30 am after already getting yourself in a horrible mess, but here I am. Now the phone is stuck at the LG logo screen, the LED flashes green and blue, and nothing happens. All I can do is to push the power button, and the process repeats.

Naturally, I cannot see any partitions any longer. Now the device seems to be REALLY dead.

Anything I can still try?!

Original problem description

I have tried, after somehow messing things up when following the guide to install LineageOS on the LG G2 (d802, international version with 32 GB), to resurrect my phone using this guide.

However, it failed to solve my problem, and when I tried to boot, the phone still showed only the LG logo, the secure booting error, and then the screen went black, just as before. I guess I should have used dd as well to copy the boot, dbi and laf partitions.

Instead, I figured maybe I should try the TWRP Recovery v2.6.3.2 instead of either TWRP v2.8.7.3 or the LineageOS Recovery image, and that probably has been my (final) mistake. Because, before, the output from gdisk looked liked this:

Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 61071360 sectors, 29.1 GiB
Model: MMC Storage
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): 98101B32-BBE2-4BF2-A06E-2BB33D000C20
Partition table holds up to 36 entries
Main partition table begins at sector 2 and ends at sector 10
First usable sector is 34, last usable sector is 61071326
Partitions will be aligned on 2-sector boundaries
Total free space is 257992 sectors (126.0 MiB)

Number Start (sector) End (sector) Size Code Name
1 32768 163839 64.0 MiB 0700 modem
2 163840 165887 1024.0 KiB FFFF sbl1
3 165888 166911 512.0 KiB FFFF dbi
4 196608 197631 512.0 KiB FFFF DDR
5 229376 231423 1024.0 KiB FFFF aboot
6 231424 233471 1024.0 KiB FFFF rpm
7 262144 294911 16.0 MiB FFFF boot
8 294912 296959 1024.0 KiB FFFF tz
9 296960 296961 1024 bytes 0700 pad
10 327680 333823 3.0 MiB FFFF modemst1
11 333824 339967 3.0 MiB FFFF modemst2
12 339968 339969 1024 bytes FFFF pad1
13 360448 393215 16.0 MiB FFFF misc
14 393216 458751 32.0 MiB 0700 persist
15 458752 491519 16.0 MiB FFFF recovery
16 491520 497663 3.0 MiB FFFF fsg
17 524288 525311 512.0 KiB FFFF fsc
18 525312 526335 512.0 KiB FFFF ssd
19 526336 526337 1024 bytes FFFF pad2
20 526338 527361 512.0 KiB FFFF encrypt
21 557056 573439 8.0 MiB 0700 drm
22 573440 589823 8.0 MiB 0700 sns
23 589824 655359 32.0 MiB FFFF laf
24 655360 720895 32.0 MiB FFFF fota
25 720896 786431 32.0 MiB 0700 mpt
26 786432 787455 512.0 KiB FFFF dbibak
27 787456 789503 1024.0 KiB FFFF rpmbak
28 789504 791551 1024.0 KiB FFFF tzbak
29 791552 791567 8.0 KiB FFFF rct
30 819200 6488063 2.7 GiB 0700 system
31 6488064 7733247 608.0 MiB 0700 cache
32 7733248 7897087 80.0 MiB 0700 tombstones
33 7897088 7929855 16.0 MiB 0700 spare
34 7929856 8028159 48.0 MiB 0700 cust
35 8028160 60948479 25.2 GiB 0700 userdata
36 60948480 61071326 60.0 MiB 0700 grow

Now, it looks like this, so I am unable to use dd to copy any files to the (now apparently deleted or at least unavailable) partitions of the LG G2:

***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory.
***************************************************************

Warning! Main partition table overlaps the first partition by 32 blocks!
You will need to delete this partition or resize it in another utility.

Warning! Secondary partition table overlaps the last partition by
33 blocks!
You will need to delete this partition or resize it in another utility.
Disk /dev/sdb: 2014208 sectors, 983.5 MiB
Model: Mighty Drive
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): DEF7EA8F-7D62-49A1-8F27-4F59EF0FDF29
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 2014174
Partitions will be aligned on 2-sector boundaries
Total free space is 0 sectors (0 bytes)

Number Start (sector) End (sector) Size Code Name
1 2 2014207 983.5 MiB 0700 Microsoft basic data

I am afraid I have no backup of the partition table other than the output above, because I only learned of this feature of gdisk when looking for solutions of this (last) issue.

Is there any way I can restore the partition table of my device?

Any help in unbricking my phone is, of course, GREATLY appreciated. :fingers-crossed: