MK802 iii bricked - Errorownload IDB failed

MK802 iii bricked - Errorownload IDB failed

Hello!

Ok, I think I bricked my MK 802 iii. My last hope is that you guys have the ultimate advice for me 

What did I do?
I tried to install a different Linux ROM on a SD-Card, where I wanted the MK802 to boot from. It is the following one:
http://www.slatedroid.com/topic/4145...i-ug802-mk808/

There is a recovery.img, which has to be flashed. I did so, booted the device to android and did a "reboot recovery" command but the boot process to Linux didnt work. I could boot to the stock android anyway, no real problem so far.

But now I think i did a terrible mistake:
I thought if i flash the recovery.img into the boot partition, it should boot straight from the sd-card, without booting android at first. I just wanted to try if this works. And from there the device doesnt boot anymore.
It always starts in "mask rom" mode directly. So i tried to recover my device by flashing a stock rom with RKBatchTool (v 1.7.) but it ended up with an error: Download IDB Failed.
And now this Error is what every try to recovery my device ends with.

What did I try?I tried to flash many different ROMs with many different Tools: FinlessROM 1.7c and Finless 1.4a with ROM FlashTool. Stock ROM old version and new version with RKBatchTool (v 1.7. & v 1.5.).
I googled like hell, found different hints to short circuit different pins: 6&7 (which brings the device in mask rom, no help, my device starts in mask rom anyway). 8&9, the peds next to the nand, i even tried to study the datasheet of the nand chip (toshiba TC58NVG6D2GTA00), but im not really an expert so it wasnt a help really.
I tried different USB ports, different USB cables, a different PC with WIN 7 (im using win 7 on my too), even a different pc with win 8. No help... 

The Error in the logs of RKBatchTool:
Code:
22:03:28 010    <Layer 1-2> Download IDB Start
22:03:28 023    <LAYER 1-2> ERROR:WriteIDBlock-->memcmp failed
22:03:28 038    <LAYER 1-2> ERROR:WriteIDBlock-->memcmp failed
22:03:28 053    <LAYER 1-2> ERROR:WriteIDBlock-->memcmp failed
22:03:28 055    <Layer 1-2> Download IDB Fail
The Logs of ROM Flash Tool:
Code:
22:02:53 462    INFO:Rewrite IDB£¬times(9)
22:02:53 462    INFO:MakeIDBlockData start
22:02:53 462    INFO:MakeEccSpareData start
22:02:53 468    INFO:WriteXIDBlock start
22:02:53 469    INFO:Writeing the 1th ID Block£¬Pos£º00009216(SEC)
22:02:53 470    INFO:Writing sector 00009216 ~ 00009231 ...
22:02:53 473    INFO:Reading sector 00009216 ~ 00009231 ...
22:02:53 476    INFO:check start
22:02:53 476    ERROR:WriteXIDBlock-->Check failed
22:02:53 477    ERROR:WriteXIDBlock failed,Errcode(1)
22:02:53 478    INFO:Rewrite IDB£¬times(10)
22:02:53 478    ERROR: WriteXIDBlock failed,Errcode(1)
22:02:53 478    Errorownload IDB failed
22:02:53 480    ERROR:MaskRomThread failed
22:02:53 481    ERROR:Run failed
RKAndroidTool:
Code:
21:36:33 183    INFO:Rewrite IDB£¬times(9)
21:36:33 183    INFO:MakeIDBlockData start
21:36:33 183    INFO:MakeEccSpareData start
21:36:33 183    INFO:WriteXIDBlock start
21:36:33 183    INFO:Writeing the 1th ID Block£¬Pos£º00018432(SEC)
21:36:33 183    INFO:Writing sector 00018432 ~ 00018447 ...
21:36:33 183    INFO:Reading sector 00018432 ~ 00018447 ...
21:36:33 199    INFO:check start
21:36:33 199    ERROR:WriteXIDBlock-->Check failed
21:36:33 199    ERROR:WriteXIDBlock failed,Errcode(1)
21:36:33 199    INFO:Rewrite IDB£¬times(10)
21:36:33 199    ERROR: WriteXIDBlock failed,Errcode(1)
21:36:33 199    Errorownload IDB failed
21:36:33 199    ERROR:MaskRomThread failed
21:36:33 199    ERROR:Run failed
Does anyone have another idea what to try??