[G Pad 10.1 Q&A, Help & Troubleshooting] surfrock66:
Before I begin, I'm probably 8/10 competent with linux and 5/10 competent with android development. I've flashed many a phone with a new ROM, recovered from some bad flashes, etc. I've never screwed anything up as bad as this.

I had the v480 upgraded to Android 5.0, but wanted to get rid of that and try Lineage. To get TWRP on there, I needed to flash the Android 4.4 kdz, which I was able to do (V48010b0.kdz). Great. I got root, but no method I tried got TWRP to load; it would flash, but then it would never boot into the recovery, it would sit at the LG screen forever. I was using TWRP_2.8.6.0_v480_bumped.img from this thread: https://xdaforums.com/g-pad-10/development/recovery-twrp2-8-5-0lgv400-410-t3049568

Here is the first screw up. I tried to re-flash the kdz file after screwing around for a while, and the Windows 7 laptop I was using with the LG tools bluescreened right in the god damned middle of the flash.. The tablet was DEAD. Full blown brick, no charging light, no nothing.

So, I found this thread and adapted it to my tablet. https://xdaforums.com/android/development/qd-9008-fix-tested-lg-v410g-pad-7-0-att-t3269057 I was able to make progress. I did NOT record the partition layout at the time, so I attempted to order the partitions based on the data in the partition filenames extracted from the kdz file:

Num	PartStart	PartName	Size	Size(K)	PartMapNumber
01	16384	modem_16384.bin	23.1M	22528	1
02	147456	sbl1_147456.bin	512K	512	2
03	149504	rpm_149504.bin	512K	512	3
04	150528	tz_150528.bin	512K	512	4
05	151552	sdi_151552.bin	512K	512	5
06	152576	aboot_152576.bin	1M	1024	6
07	156672	rpmb_156672.bin	512K	512	7
08	157696	tzb_157696.bin	512K	512	8
09	158720	abootb_158720.bin	1M	1024	9
10	212992	persist_212992.bin	5.2M	5120	15
11	278528	laf_278528.bin	18.4M	17920	16
12	327680	boot_327680.bin	12.6M	12288	17
13	376832	recovery_376832.bin	13.1M	12800	18
14	444416	sbl1b_444416.bin	512K	512	22
15	447488	rct_447488.bin	512K	512	24
16	492544	factory_492544.bin	14.2M	13824	28
17	688128	cust_688128.bin	9.4M	9216	31
18	901120	system_901120.bin	134.7M	131584
19	1164296	system_1164296.bin	512K	512
20	1168408	system_1168408.bin	131.6M	128516
21	1429520	system_1429520.bin	133.2M	130048
22	1692696	system_1692696.bin	131.6M	128512
23	1953808	system_1953808.bin	133.2M	130048
24	2216984	system_2216984.bin	131.6M	128512
25	2478096	system_2478096.bin	133.2M	130048
26	2741272	system_2741272.bin	131.6M	128512
27	3002384	system_3002384.bin	133.2M	130048
28	3265560	system_3265560.bin	131.6M	128512
29	3526672	system_3526672.bin	132.1M	129024
30	3788816	system_3788816.bin	132.1M	129024
31	4050960	system_4050960.bin	47.7M	46592
32	4308992	system_4308992.bin	512K	512
33	4571136	system_4571136.bin	512K	512
34	4833280	system_4833280.bin	512K	512
35	15269855	BackupGPT_15269855.bin	512K	512

The "Part Map Number" column is something I added much later in the troubleshooting. SO...I basically guessed the partition layout for this, and got it close...doing this, and preparing an sd card, I was able to get TWRP to boot off of an SD card. HUZZAH. Now I'm able to get adb going and get into the tablet! I tried to flash a .zip file for CM12 or Lineage14.1...neither "worked" and rebooting to system/recovery/or bootloader just launched back into TWRP.

Now is where I'm in over my head. I was able to get the partition layout by doing this:

~ # ls -asl /dev/block/platform/msm_sdcc.1/by-name/
total 0
__bionic_open_tzdata: couldn't find any tzdata when looking for localtime!
__bionic_open_tzdata: couldn't find any tzdata when looking for GMT!
__bionic_open_tzdata: couldn't find any tzdata when looking for posixrules!
lrwxrwxrwx root root 1970-01-02 21:57 DDR -> /dev/block/mmcblk0p25
lrwxrwxrwx root root 1970-01-02 21:57 aboot -> /dev/block/mmcblk0p6
lrwxrwxrwx root root 1970-01-02 21:57 abootb -> /dev/block/mmcblk0p9
lrwxrwxrwx root root 1970-01-02 21:57 boot -> /dev/block/mmcblk0p17
lrwxrwxrwx root root 1970-01-02 21:57 cache -> /dev/block/mmcblk0p33
lrwxrwxrwx root root 1970-01-02 21:57 cust -> /dev/block/mmcblk0p31
lrwxrwxrwx root root 1970-01-02 21:57 drm -> /dev/block/mmcblk0p26
lrwxrwxrwx root root 1970-01-02 21:57 eksst -> /dev/block/mmcblk0p10
lrwxrwxrwx root root 1970-01-02 21:57 encrypt -> /dev/block/mmcblk0p23
lrwxrwxrwx root root 1970-01-02 21:57 factory -> /dev/block/mmcblk0p28
lrwxrwxrwx root root 1970-01-02 21:57 fota -> /dev/block/mmcblk0p29
lrwxrwxrwx root root 1970-01-02 21:57 fsc -> /dev/block/mmcblk0p20
lrwxrwxrwx root root 1970-01-02 21:57 fsg -> /dev/block/mmcblk0p19
lrwxrwxrwx root root 1970-01-02 21:57 grow -> /dev/block/mmcblk0p35
lrwxrwxrwx root root 1970-01-02 21:57 laf -> /dev/block/mmcblk0p16
lrwxrwxrwx root root 1970-01-02 21:57 misc -> /dev/block/mmcblk0p14
lrwxrwxrwx root root 1970-01-02 21:57 modem -> /dev/block/mmcblk0p1
lrwxrwxrwx root root 1970-01-02 21:57 modemst1 -> /dev/block/mmcblk0p12
lrwxrwxrwx root root 1970-01-02 21:57 modemst2 -> /dev/block/mmcblk0p13
lrwxrwxrwx root root 1970-01-02 21:57 mpt -> /dev/block/mmcblk0p30
lrwxrwxrwx root root 1970-01-02 21:57 pad -> /dev/block/mmcblk0p11
lrwxrwxrwx root root 1970-01-02 21:57 persist -> /dev/block/mmcblk0p15
lrwxrwxrwx root root 1970-01-02 21:57 rct -> /dev/block/mmcblk0p24
lrwxrwxrwx root root 1970-01-02 21:57 recovery -> /dev/block/mmcblk0p18
lrwxrwxrwx root root 1970-01-02 21:57 rpm -> /dev/block/mmcblk0p3
lrwxrwxrwx root root 1970-01-02 21:57 rpmb -> /dev/block/mmcblk0p7
lrwxrwxrwx root root 1970-01-02 21:57 sbl1 -> /dev/block/mmcblk0p2
lrwxrwxrwx root root 1970-01-02 21:57 sbl1b -> /dev/block/mmcblk0p22
lrwxrwxrwx root root 1970-01-02 21:57 sdi -> /dev/block/mmcblk0p5
lrwxrwxrwx root root 1970-01-02 21:57 sns -> /dev/block/mmcblk0p27
lrwxrwxrwx root root 1970-01-02 21:57 ssd -> /dev/block/mmcblk0p21
lrwxrwxrwx root root 1970-01-02 21:57 system -> /dev/block/mmcblk0p32
lrwxrwxrwx root root 1970-01-02 21:57 tz -> /dev/block/mmcblk0p4
lrwxrwxrwx root root 1970-01-02 21:57 tzb -> /dev/block/mmcblk0p8
lrwxrwxrwx root root 1970-01-02 21:57 userdata -> /dev/block/mmcblk0p34

There is a msm_sdcc.2 as well with the same partition layout. At this point, I figured, I could push the .dz files for each partition to /sdcard (which was still populated with android stuff) then just flash the required partitions. I ran mount to see which was mounted where:

~ # mount
rootfs on / type rootfs (rw)
tmpfs on /dev type tmpfs (rw,seclabel,nosuid,relatime,size=441232k,nr_inodes=110308,mode=755)
devpts on /dev/pts type devpts (rw,seclabel,relatime,mode=600)
proc on /proc type proc (rw,relatime)
sysfs on /sys type sysfs (rw,seclabel,relatime)
selinuxfs on /sys/fs/selinux type selinuxfs (rw,relatime)
tmpfs on /tmp type tmpfs (rw,seclabel,relatime,size=441232k,nr_inodes=110308)
/dev/block/mmcblk0p34 on /data type ext4 (rw,seclabel,relatime,resuid=1000,data=ordered)
/dev/block/mmcblk0p34 on /sdcard type ext4 (rw,seclabel,relatime,resuid=1000,data=ordered)
/dev/block/mmcblk0p33 on /cache type ext4 (rw,seclabel,relatime,data=ordered)
/dev/block/mmcblk1p1 on /external_sd type vfat (rw,relatime,fmask=0000,dmask=0000,allow_utime=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)

Then planned to completely destroy the system with this. I ran the following:

dd if=/sdcard/V48010b0/PrimaryGPT_0.bin of=/dev/block/mmcblk0; sleep 2
dd if=/sdcard/V48010b0/modem_16384.bin of=/dev/mmcblk0p1; sleep 2
dd if=/sdcard/V48010b0/sbl1_147456.bin of=/dev/mmcblk0p2; sleep 2
dd if=/sdcard/V48010b0/rpm_149504.bin of=/dev/mmcblk0p3; sleep 2
dd if=/sdcard/V48010b0/tz_150528.bin of=/dev/mmcblk0p4; sleep 2
dd if=/sdcard/V48010b0/sdi_151552.bin of=/dev/mmcblk0p5; sleep 2
dd if=/sdcard/V48010b0/aboot_152576.bin of=/dev/mmcblk0p6; sleep 2
dd if=/sdcard/V48010b0/rpmb_156672.bin of=/dev/mmcblk0p7; sleep 2
dd if=/sdcard/V48010b0/tzb_157696.bin of=/dev/mmcblk0p8; sleep 2
dd if=/sdcard/V48010b0/abootb_158720.bin of=/dev/mmcblk0p9; sleep 2
dd if=/sdcard/V48010b0/persist_212992.bin of=/dev/mmcblk0p15; sleep 2
#dd if=/sdcard/V48010b0/laf_278528.bin of=/dev/mmcblk0p16; sleep 2
dd if=/sdcard/V48010b0/boot_327680.bin of=/dev/mmcblk0p17; sleep 2
dd if=/sdcard/V48010b0/recovery_376832.bin of=/dev/mmcblk0p18; sleep 2
#dd if=/sdcard/V48010b0/TWRP_2.8.6.0_v480_bumped.img of=/dev/mmcblk0p18; sleep 2
#dd if=/sdcard/V48010b0/TWRP_3.0.3-0_v480.img of=/dev/mmcblk0p18; sleep 2
dd if=/sdcard/V48010b0/sbl1b_444416.bin of=/dev/mmcblk0p22; sleep 2
dd if=/sdcard/V48010b0/rct_447488.bin of=/dev/mmcblk0p24; sleep 2
dd if=/sdcard/V48010b0/factory_492544.bin of=/dev/mmcblk0p28; sleep 2
dd if=/sdcard/V48010b0/cust_688128.bin of=/dev/mmcblk0p31; sleep 2

My understanding is, in theory, this should COMPLETELY blow away the internal storage of the device (flashing the primary GPT table) and then write over the important partitions. If I can get to TWRP, I should be able to flash a rom zip. So I did that...removed the SD card, and the tablet won't do anything. Put the SD card back in, did the whole "boot from SD" thing from before...TWRP comes back, ADB is up...Android files in /sdcard are still there, so I'm wondering if it didn't wipe! So, I figure maybe the block device was the wrong one...I dd'd the partitions at "mmcblk1" instead of 0. Same thing. External SD is unmodified, /sdcard directory is still there.

By this point I was confused. I got another MicroSD card and tried to set it up like I did the first one. I cannot get the tablet to boot. Put the original microSD card back in...boot to TWRP and nothing else. I have no idea what is running from what. I finally, out of desperation, decide to "dd if=/dev/zero of=/dev/mmcblk0" just to be sure I'm starting from scratch...finish that, restart...tablet comes back up to TWRP when SD card is inserted WITH data in the /sdcard folder.

So now I'm stuck. I feel like having ADB access and a running linux shell means I should be able to get something loading somewhere. I have parted on there, but it just gives me partition errors based on what I assume is the GPT table being flashed insanely:

/sdcard # parted /dev/block/mmcblk0
GNU Parted 1.8.8.1.179-aef3
Using /dev/block/mmcblk0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
print
Error: The backup GPT table is not at the end of the disk, as it should be.
This might mean that another operating system believes the disk is smaller.
Fix, by moving the backup to the end (and removing the old backup)?
Fix/Ignore/Cancel? fix
fix
Warning: Not all of the space available to /dev/block/mmcblk0 appears to be
used, you can fix the GPT to use all of the space (an extra 15507456 blocks) or
continue with the current setting?
Fix/Ignore? fix
fix
Error: Can't have the end before the start!

Just to be thorough:

/sdcard # df -h
Filesystem Size Used Available Use% Mounted on
tmpfs 430.9M 16.0K 430.9M 0% /dev
tmpfs 430.9M 16.0K 430.9M 0% /tmp
/dev/block/mmcblk0p34
11.2G 3.7G 7.4G 34% /data
/dev/block/mmcblk0p34
11.2G 3.7G 7.4G 34% /sdcard
/dev/block/mmcblk0p33
888.5M 14.5M 874.1M 2% /cache
/dev/block/mmcblk1p1 64.0M 21.9M 42.0M 34% /external_sd

So, I'm not sure what to do now. I have all the .dz files from Android 4.4 and 5.0.2, I have 2 custom rom files for CM and LOS, 2 sets of OpenGapps, TWRP, kdz files, and a working adb shell from a TWRP install I'm not sure where it's being executed from. I feel like it's working to a state I should be able to get out of this, but everything I try is failing. Am I hosed or do I have an option to get out of this? I can provide any output needed...this was interesting to me:

/proc # cat partitions
major minor #blocks name

179 0 15388672 mmcblk0
179 1 65536 mmcblk0p1
179 2 1024 mmcblk0p2
179 3 512 mmcblk0p3
179 4 512 mmcblk0p4
179 5 512 mmcblk0p5
179 6 2048 mmcblk0p6
179 7 512 mmcblk0p7
179 8 512 mmcblk0p8
179 9 2048 mmcblk0p9
179 10 512 mmcblk0p10
179 11 2048 mmcblk0p11
179 12 3072 mmcblk0p12
179 13 3072 mmcblk0p13
179 14 16384 mmcblk0p14
179 15 32768 mmcblk0p15
179 16 24576 mmcblk0p16
179 17 24576 mmcblk0p17
179 18 24576 mmcblk0p18
179 19 3072 mmcblk0p19
179 20 512 mmcblk0p20
179 21 512 mmcblk0p21
179 22 1024 mmcblk0p22
179 23 512 mmcblk0p23
179 24 512 mmcblk0p24
179 25 512 mmcblk0p25
179 26 8192 mmcblk0p26
179 27 8192 mmcblk0p27
179 28 24576 mmcblk0p28
179 29 32768 mmcblk0p29
179 30 32768 mmcblk0p30
179 31 106496 mmcblk0p31
259 0 2097152 mmcblk0p32
259 1 925696 mmcblk0p33
259 2 11911168 mmcblk0p34
259 3 9223372036847026159 mmcblk0p35
179 32 4096 mmcblk0rpmb
179 64 31166976 mmcblk1
179 65 65536 mmcblk1p1
179 66 1024 mmcblk1p2
179 67 512 mmcblk1p3
179 68 512 mmcblk1p4
179 69 512 mmcblk1p5
179 70 2048 mmcblk1p6
179 71 512 mmcblk1p7
179 72 512 mmcblk1p8
179 73 2048 mmcblk1p9
179 74 512 mmcblk1p10
179 75 2048 mmcblk1p11
179 76 3072 mmcblk1p12
179 77 3072 mmcblk1p13
179 78 16384 mmcblk1p14
179 79 32768 mmcblk1p15
179 80 24576 mmcblk1p16
179 81 24576 mmcblk1p17
179 82 24576 mmcblk1p18
179 83 3072 mmcblk1p19
179 84 512 mmcblk1p20
179 85 512 mmcblk1p21
179 86 1024 mmcblk1p22
179 87 512 mmcblk1p23
179 88 512 mmcblk1p24
179 89 512 mmcblk1p25
179 90 8192 mmcblk1p26
179 91 8192 mmcblk1p27
179 92 24576 mmcblk1p28
179 93 32768 mmcblk1p29
179 94 32768 mmcblk1p30
179 95 106496 mmcblk1p31
259 4 2097152 mmcblk1p32
259 5 925696 mmcblk1p33
259 6 11911168 mmcblk1p34
259 7 9223372036847026159 mmcblk1p35