[Dell Venue] shanx_verma:
Thank You for the reply.

I see, here are the links to the images -

Error part 1 - http://imgur.com/2k4Njrl

Error part 2 - http://imgur.com/G1YsNlh

Error part 3 - http://imgur.com/aLIWGvd

Oh, and by the way,

I've now K.O'd the GPT via gdisk, and using the fastboot oem partition command, repartitioned it.

But gdisk still shows GPT as damaged, and also when I choose to write partition table, it doesn't do it but throws an error. Please suggest how I can repair it. Have a look -

# gdisk /dev/block/mmcblk0
gdisk /dev/block/mmcblk0
GPT fdisk (gdisk) version 0.8.10

Caution: invalid backup GPT header, but valid main header; regenerating
backup header from main header.

Warning! One or more CRCs don't match. You should repair the disk!

Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: damaged

****************************************************************************
Caution: Found protective or hybrid MBR and corrupt GPT. Using GPT, but disk
verification and recovery are STRONGLY recommended.
****************************************************************************

Command (? for help): v
v

Caution: The CRC for the backup partition table is invalid. This table may
be corrupt. This program will automatically create a new backup partition
table when you save your partitions.

Identified 1 problems!

Command (? for help): x
x

Expert command (? for help): e
e
Relocating backup data structures to the end of the disk

Expert command (? for help): p
p
Disk /dev/block/mmcblk0: 30736384 sectors, 14.7 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 71589E8D-3642-5A42-E379-AEF60BB306B7
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 30736350
Partitions will be aligned on 8-sector boundaries
Total free space is 16357 sectors (8.0 MiB)

Number Start (sector) End (sector) Size Code Name
1 40 524327 256.0 MiB 0700 reserved
2 524328 589863 32.0 MiB 0700 panic
3 589864 852007 128.0 MiB 0700 factory
4 852008 1114151 128.0 MiB 0700 misc
5 1114152 1376295 128.0 MiB 0700 config
6 1376296 3473447 1024.0 MiB 0700 cache
7 3473448 3522599 24.0 MiB 0700 logs
8 3522600 5619751 1024.0 MiB 0700 system
9 5619752 30719999 12.0 GiB 0700 data

Expert command (? for help): m
m

Command (? for help): t
t
Partition number (1-9): 1
1
Current type is 'Microsoft basic data'
Hex code or GUID (L to show codes, Enter = 8300): ef00
ef00
Changed type of partition to 'EFI System'

Command (? for help): t
t
Partition number (1-9): 2
2
Current type is 'Microsoft basic data'
Hex code or GUID (L to show codes, Enter = 8300): ef00
ef00
Changed type of partition to 'EFI System'

Command (? for help):b
b
Enter backup filename to save: default
default
The operation has completed successfully.

Command (? for help): x
x

Expert command (? for help):e
e
Relocating backup data structures to the end of the disk

Expert command (? for help): r
r

Recovery/transformation command (? for help):v
v

Caution: The CRC for the backup partition table is invalid. This table may
be corrupt. This program will automatically create a new backup partition
table when you save your partitions.

Identified 1 problems!

Recovery/transformation command (? for help):w
w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
y
OK; writing new GUID partition table (GPT) to /dev/block/mmcblk0.
Unable to save backup partition table! Perhaps the 'e' option on the experts'
menu will resolve this problem.
Warning! An error was reported when writing the partition table! This error
MIGHT be harmless, or the disk might be damaged! Checking it is advisable.

Expert command (? for help):e
e
Relocating backup data structures to the end of the disk

Expert command (? for help): w
w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
y
OK; writing new GUID partition table (GPT) to /dev/block/mmcblk0.
Unable to save backup partition table! Perhaps the 'e' option on the experts'
menu will resolve this problem.
Warning! An error was reported when writing the partition table! This error
MIGHT be harmless, or the disk might be damaged! Checking it is advisable.

Also, I'm formatting the partitions with mke2fs as I type.

/config and /cache formatted fine.

/factory didn't format during the tethered recovery session, said it's in use by the system as of then.

So I tried to format logs, /system and /data as well.

Here is the result so far -

# mke2fs -t ext4 /dev/block/mmcblk0p7 (- LOGS)
mke2fs -t ext4 /dev/block/mmcblk0p7
mke2fs 1.42.9 (28-Dec-2013)

Warning: the fs_type small is not defined in mke2fs.conf

Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1536 inodes, 6144 blocks
307 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=8388608
1 block group
32768 blocks per group, 32768 fragments per group
1536 inodes per group

Allocating group tables: done
Writing inode tables: done
Creating journal (1024 blocks): done
Writing superblocks and filesystem accounting information: done

# mke2fs -t ext4 /dev/block/mmcblk0p8 (- SYSTEM)
mke2fs -t ext4 /dev/block/mmcblk0p8
mke2fs 1.42.9 (28-Dec-2013)
Discarding device blocks: 4096/262144

failed - I/O error
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=268435456
8 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376

Allocating group tables: done
Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: 0/8
Warning, had trouble writing out superblocks.

Although it doesn't seem too good, I'll get back with the result. Will edit the same post with the full version of the output window of your tethered recovery on my PC.

-EDIT-

After this I formatted system and data using the "Change File System" menu from inside the wipe menu of the tethered TWRP itself. Chose EXT4 for both. The system partition went fine, formatted, but the data partition, while formatting, gave these errors -

Formatting Data using make_ext4fs function.
[COLOR=RED]E:Unable to mount '/data'
E:Unable to mount storage.
E:Unable to mount '/data'
E:Unknown MTP message type: 1
E:Error changing file system.[/COLOR]
Updating partition details. . .
[COLOR=RED]E:Unable to mount '/data'[/COLOR]
. . .done
[COLOR=RED]E:Unable to mount storage.[/COLOR]

Here the newest images -

http://imgur.com/870wOSv

http://imgur.com/UIlvrP1

Major thanks there, both for the tethered recovery and for helping me out! :)

How to proceed now? :)