[LG Optimus 4X HD] skydev:
Alright, right now i am flashing my own cooked kdz file with Superuser carefully added to the system.img.

Wish me good luck.

Well,... failed to update at 36%

[R&D Test Tools Log File]

02:52:25 : Launching SW update
02:52:25 : Unpacking KDZ
02:52:30 : KDZ file extraced
02:52:33 : Files were extracted.
02:52:33 : LGMobileDL Load.
02:52:33 : Port = -1
02:52:33 : Connecting to phone
02:52:46 : Check Phone mode = 2
02:52:46 : Phone type check.......
02:52:47 : LGMobileDL.DLL Loading....
02:52:48 : _SetAuthMark Fail
02:52:48 : _SetAuthMark Ok : wAuthMark(65535)
02:52:48 : _DetachDLL Call
02:52:48 : _DetachDLL Call End
02:52:48 : Param : Path = C:\ProgramData\LGMOBILEAX\Phone\GP880AT-00-V20a-EUR-XXX-MAR-04-2013+0.dz
02:52:48 : Param : moduleDir =
02:52:48 : Param : waitTime = 0
02:52:48 : Param : UsbHighSpeed = 1
02:52:48 : Param : PhoneMode = 2
02:52:48 : Param : BinVersion = P880
02:52:48 : Param : AuthMark = 65535
02:52:48 : Call fn_StartUpgrade
02:52:48 : 3GQCT : wParam = 2005, lParam = 0
02:52:48 : 3GQCT : wParam = 2005, lParam = 4
02:52:49 : 3GQCT : wParam = 2003, lParam = 5
02:52:49 : 3GQCT : wParam = 2005, lParam = 4
02:52:59 : 3GQCT : wParam = 2005, lParam = 0
02:52:59 : 3GQCT : wParam = 2005, lParam = 1
02:52:59 : 3GQCT : wParam = 2003, lParam = 3015
02:52:59 : 3GQCT : wParam = 2003, lParam = 1
02:52:59 : 3GQCT : wParam = 2005, lParam = 1
02:52:59 : 3GQCT : wParam = 2003, lParam = 1
02:52:59 : 3GQCT : wParam = 2005, lParam = 1
02:52:59 : 3GQCT : wParam = 2005, lParam = 2
02:52:59 : 3GQCT : wParam = 2005, lParam = 3
02:52:59 : 3GQCT : wParam = 2003, lParam = 3
02:52:59 : 3GQCT : wParam = 2005, lParam = 3
02:52:59 : 3GQCT : wParam = 2005, lParam = 4
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2007, lParam = 0
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2003, lParam = 201
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2003, lParam = 401
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2003, lParam = 200
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2003, lParam = 202
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:52:59 : 3GQCT : wParam = 2003, lParam = 203
02:52:59 : 3GQCT : wParam = 2005, lParam = 5
02:53:02 : 3GQCT : wParam = 2005, lParam = 10
02:53:02 : 3GQCT : wParam = 2003, lParam = 204
02:53:02 : 3GQCT : wParam = 2005, lParam = 10
02:53:16 : 3GQCT : wParam = 2003, lParam = 205
02:53:16 : 3GQCT : wParam = 2005, lParam = 10
02:53:16 : 3GQCT : wParam = 2003, lParam = 206
02:53:16 : 3GQCT : wParam = 2005, lParam = 10
02:53:16 : 3GQCT : wParam = 2003, lParam = 207
02:53:16 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 208
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 210
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 230
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 250
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 270
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 290
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 310
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 211
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:17 : 3GQCT : wParam = 2003, lParam = 231
02:53:17 : 3GQCT : wParam = 2005, lParam = 10
02:53:18 : 3GQCT : wParam = 2003, lParam = 251
02:53:18 : 3GQCT : wParam = 2005, lParam = 10
02:53:18 : 3GQCT : wParam = 2003, lParam = 271
02:53:18 : 3GQCT : wParam = 2005, lParam = 10
02:53:18 : 3GQCT : wParam = 2003, lParam = 291
02:53:18 : 3GQCT : wParam = 2005, lParam = 10
02:53:19 : 3GQCT : wParam = 2003, lParam = 311
02:53:19 : 3GQCT : wParam = 2005, lParam = 10
02:53:19 : 3GQCT : wParam = 2003, lParam = 212
02:53:19 : 3GQCT : wParam = 2005, lParam = 10
02:53:20 : 3GQCT : wParam = 2003, lParam = 232
02:53:20 : 3GQCT : wParam = 2005, lParam = 10
02:53:20 : 3GQCT : wParam = 2003, lParam = 252
02:53:20 : 3GQCT : wParam = 2005, lParam = 10
02:53:20 : 3GQCT : wParam = 2003, lParam = 272
02:53:20 : 3GQCT : wParam = 2005, lParam = 10
02:53:20 : 3GQCT : wParam = 2003, lParam = 292
02:53:20 : 3GQCT : wParam = 2005, lParam = 10
02:53:24 : 3GQCT : wParam = 2005, lParam = 11
02:53:24 : 3GQCT : wParam = 2003, lParam = 312
02:53:24 : 3GQCT : wParam = 2005, lParam = 11
02:53:24 : 3GQCT : wParam = 2003, lParam = 213
02:53:24 : 3GQCT : wParam = 2005, lParam = 11
02:53:24 : 3GQCT : wParam = 2003, lParam = 233
02:53:24 : 3GQCT : wParam = 2005, lParam = 11
02:53:25 : 3GQCT : wParam = 2003, lParam = 253
02:53:25 : 3GQCT : wParam = 2005, lParam = 11
02:53:25 : 3GQCT : wParam = 2003, lParam = 273
02:53:25 : 3GQCT : wParam = 2005, lParam = 11
02:53:25 : 3GQCT : wParam = 2003, lParam = 293
02:53:25 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 313
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 214
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 234
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 254
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 274
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:27 : 3GQCT : wParam = 2003, lParam = 294
02:53:27 : 3GQCT : wParam = 2005, lParam = 11
02:53:30 : 3GQCT : wParam = 2005, lParam = 12
02:53:36 : 3GQCT : wParam = 2005, lParam = 13
02:53:42 : 3GQCT : wParam = 2005, lParam = 14
02:53:49 : 3GQCT : wParam = 2005, lParam = 15
02:53:54 : 3GQCT : wParam = 2005, lParam = 16
02:53:59 : 3GQCT : wParam = 2005, lParam = 17
02:54:06 : 3GQCT : wParam = 2005, lParam = 18
02:54:12 : 3GQCT : wParam = 2005, lParam = 19
02:54:15 : 3GQCT : wParam = 2003, lParam = 314
02:54:15 : 3GQCT : wParam = 2005, lParam = 19
02:54:15 : 3GQCT : wParam = 2003, lParam = 399
02:54:15 : 3GQCT : wParam = 2005, lParam = 19
02:54:15 : 3GQCT : wParam = 2003, lParam = 400
02:54:15 : 3GQCT : wParam = 2005, lParam = 19
02:54:15 : 3GQCT : wParam = 2003, lParam = 403
02:54:15 : 3GQCT : wParam = 2005, lParam = 19
02:54:15 : 3GQCT : wParam = 2003, lParam = 1
02:54:15 : 3GQCT : wParam = 2005, lParam = 19
02:54:16 : 3GQCT : wParam = 2003, lParam = 404
02:54:16 : 3GQCT : wParam = 2005, lParam = 19
02:54:16 : 3GQCT : wParam = 2003, lParam = 704
02:54:16 : 3GQCT : wParam = 2005, lParam = 20
02:54:18 : 3GQCT : wParam = 2003, lParam = 407
02:54:18 : 3GQCT : wParam = 2005, lParam = 20
02:54:18 : 3GQCT : wParam = 2003, lParam = 606
02:54:18 : 3GQCT : wParam = 2005, lParam = 20
02:54:18 : 3GQCT : wParam = 2003, lParam = 706
02:54:18 : 3GQCT : wParam = 2005, lParam = 20
02:54:20 : 3GQCT : wParam = 2003, lParam = 608
02:54:20 : 3GQCT : wParam = 2005, lParam = 20
02:54:20 : 3GQCT : wParam = 2003, lParam = 708
02:54:20 : 3GQCT : wParam = 2005, lParam = 21
02:54:20 : 3GQCT : wParam = 2005, lParam = 22
02:54:21 : 3GQCT : wParam = 2005, lParam = 23
02:54:21 : 3GQCT : wParam = 2005, lParam = 24
02:54:21 : 3GQCT : wParam = 2005, lParam = 25
02:54:21 : 3GQCT : wParam = 2005, lParam = 26
02:54:22 : 3GQCT : wParam = 2005, lParam = 27
02:54:22 : 3GQCT : wParam = 2005, lParam = 28
02:54:22 : 3GQCT : wParam = 2005, lParam = 29
02:54:24 : 3GQCT : wParam = 2003, lParam = 609
02:54:24 : 3GQCT : wParam = 2005, lParam = 29
02:54:24 : 3GQCT : wParam = 2003, lParam = 709
02:54:24 : 3GQCT : wParam = 2005, lParam = 30
02:54:25 : 3GQCT : wParam = 2005, lParam = 31
02:54:25 : 3GQCT : wParam = 2005, lParam = 32
02:54:25 : 3GQCT : wParam = 2005, lParam = 33
02:54:25 : 3GQCT : wParam = 2005, lParam = 34
02:54:26 : 3GQCT : wParam = 2005, lParam = 35
02:54:26 : 3GQCT : wParam = 2005, lParam = 36
02:54:28 : 3GQCT : wParam = 2003, lParam = 610
02:54:28 : 3GQCT : wParam = 2005, lParam = 36
02:54:28 : 3GQCT : wParam = 2003, lParam = 710
02:54:28 : 3GQCT : wParam = 2005, lParam = 36
02:54:28 : 3GQCT : wParam = 2010, lParam = 15

As I see, error code is 15.

Any idea what is that code? Maybe i messed up with md5 check or something.

Edit: in normal kdz file instead of 2010, 15 error it outputs 2003, 710. Can someone decrypt this?

Edit2: Alright, i see possible problem: something have trashed when i did all those ping-pong compressions and decompressions

skydev@SkydevPC:~/system_20a/work$ printf "\x1f\x8b\x08\x00\x00\x00\x00\x00" |cat - new_system |gzip -dc > new_system_unpack

gzip: stdin: invalid compressed data--format violated

Edit3: Confirmation, i forgot to put in XFL and OS flags (ref http://www.gzip.org/zlib/rfc-gzip.html)