I took the base 5120 file from nyet and modified it to what I believe is correct, ran it through me7sum and it gave me this :

Microsoft Windows [Version 10.0.10586]
(c) 2015 Microsoft Corporation. All rights reserved.

C:\Users\Tyler>me7sum 5120_2_1.bin 5120_2_1_c.bin
ME7Tool (v1.0.3) [Management tool for Bosch ME7.x firmwares]
Inspiration from Andy Whittaker's tools and information.
Written by 360trev and nyet [BSD License Open Source].

Attempting to open firmware file '5120_2_1.bin'

Step #1: Reading ROM info ..
 Searching for EPK signature...OK
 Searching for ECUID table...OK
 EPK         : '40/1/ME7.1/5/6005.01//22m/DstC2o/011200//'
 Part Number : '8D0907551M  '
 Engine ID   : '2.7l V6/5VT     '
 SW Version  : '0002'
 HW Number   : '0261207143'
 SW Number   : '1037360857'

Step #2: Reading ROMSYS ..
 Startup section: word[0x008000]+word[0x00FFFE]
 @008038 Add=0x013225 CalcAdd=0x013225  ADD OK
 Program pages: 8k page first+last in 0x0000-0xFFFF and 0x20000-0xFFFFF
 @00803c Add=0xABDDC5 CalcAdd=0xABDDC5  ADD OK
 All param page: word[0x010000]+word[0x01FFFE]
 @01b9b0 Add=0x00971D CalcAdd=0x00971D  ADD OK

Step #3: Reading RSA signatures ..
 Searching for RSA offset #0...missing
 Searching for RSA offset #1...missing

Step #4: Finding CRC table(s) ..
 Searching for CRC table(s)...OK
 CRC table(s) OK

Step #5: Reading Main Data Checksums ..
 Searching for main data CRC pre block...missing
 Searching for main data CRC/csum blocks...OK
 Searching for main data CRC offsets...OK
 Searching for main data checksum offsets...missing
 Main CRCs:
 1) 0x010002-0x013FFE @7a866 CRC: 649B8505 CalcCRC: 54B4EA66    ** FIXED **
 2) 0x014252-0x017F4E @7a86c CRC: 3D5CD35D CalcCRC: C4A1C502    ** FIXED **
 3) 0x018192-0x01FBB0 @7a872 CRC: 63BCF7AB CalcCRC: 2FD8A617    ** FIXED **

Step #6: Reading Main Program Checksums ..
 Searching for main program checksum..OK
 ROM Checksum Block Offset Table @1e75a [16 bytes]:
 1) 0x000000-0x00FBFF CalcChk: 47AF0B2F
    0x00FC00-0x01FFFF CalcChk: 29037373 CalcCRC: FDBAEDCC SKIPPED
 2) 0x020000-0x0FFFFF
    <fffe0>  Chk: 9CC24884 CalcChk: 9CC1335B ** FIXED **

Step #7: Reading Multipoint Checksum Blocks ..
 Searching for multipoint block descriptor #1...OK
 1) <14224>  0x024000-0x02658D Chk: 0B08F804 CalcChk: 0B08F804 OK
 2) <14234>  0x014000-0x014243 Chk: 00540FE9 CalcChk: 00540FE9 OK (i)
 3) <14244>  0xFFFFFFFF-0xFFFFFFFF  END
 Multipoint #1: [2 blocks x <16> = 32 bytes]
 Searching for multipoint block descriptor #2...OK
 1) <1fbb2>  0x000000-0x003FFF Chk: 0FA0F5CF Boot: (whitelisted) OK
 2) <1fbc2>  0x004000-0x007FFF Chk: 0F4716B3 Boot: (whitelisted) OK
 3) <1fbd2>  0x000000-0x003FFF Chk: 0FF728A4 CalcChk: 0FF728A4 OK
 4) <1fbe2>  0x004000-0x007FFF Chk: 0F68CD6E CalcChk: 0F68CD6E OK
 Multipoint #2: [66 blocks x <16> = 1056 bytes]

*** Found 73 checksums in 5120_2_1.bin

Attempting to output corrected firmware file '5120_2_1_c.bin'
├╛ Opening '5120_2_1_c.bin' file for writing
├╛ Writing to file
├╛ Validating size correct 1048576=1048576
├╛ All OK, closing file

*** DONE! 10/10 error(s) in 5120_2_1.bin corrected in 5120_2_1_c.bin! ***

C:\Users\Tyler>

I then flashed it and it bricked my ECU. I restored, flashed again same result. running it through me7check yields

Microsoft Windows [Version 10.0.10586]
(c) 2015 Microsoft Corporation. All rights reserved.

C:\Users\Tyler>me7check 5120_2_1_c.bin
==============================================================================
me7check v1.12 (c) mki, 06/2004-05/2012
Checking file 5120_2_1_c.bin (size=1048576)
Reading Version Strings...
-> Bootrom Version = embedded in CPU, asume 05.12/05.32
-> EPK = 40/1/ME7.1/5/6005.01//22m/DstC2o/011200//
-> Contents of ECUID data table:
   - '0261207143'         (SSECUHN)
   - '1037360857'         (SSECUSN)
   - '8D0907551M  '       (VAG part number)
   - '0002'               (VAG sw number)
   - '2.7l V6/5VT     '   (engine id)
-> Contents of ECUID data table:
   - 'HW_MAN004'

-> No errors found. File is OK.   ******************

Can someone verify this checksum for me? Any other reason it would brick my ECU?

Thanks

no, any of the other files made with the 8D0907551M base don't give me any trouble. I've probably flashed it 50+ times.

it is an ecu out of a 2000 A6, only thing I can think is something there isn't compatible.

I guess I should've mentioned, yesterday after I bricked it twice I flashed my previous file and all was well.

when I flash it, it flashes fine and disconnects. Then, I can connect again with nef if I don't remove power. If I unplug, I cannot connect with nefmoto or vag com and my car won't start. No way to tell if I am getting any codes or whatever.

bingo. thanks man