Need a Checksum Help

[TN-Notebooks]

Hallo

a other Forum gave me the Idea to ask here -- may The Robman can help with this Problem.

Together with a Friend near Chicago i am fixing Synology NAS and Help Users.
Sometimes it happens that a Update corrupt all Data that are stored on the USB Flash Drive which is needed to boot the Unit.
I am Able to clone that Modul already but i need to change the Serial Number and the MAC Adress to the original Values of the affected Unit.

The Position Of Serial Number and Mac Adresses is found in the Vender File and in the full Image File of the Drive.

The Problem is that if i change the Serial and the MAC Adress the Serial is Blanked out and a random MAC Adress is shown.
That happens because the Datas are not valid due to a Check sum
The original Values are Lost due to the corrupted drives.

Exaple 1
First is Serial Number the other two Mac Adress

Original Vender File working
1680NZN934402 --> CHK=763
00 11 32 62 DD E7 -> 69
00 11 32 62 DD E8 -> 6A

changed in Vender to
1760NLN574900 --> CHK=763
00 11 32 6D C6 99 -> 69
00 11 32 6D C6 9A -> 6A

Indicated at boot in the Synology Assistant as
Serial Number : Blanked
00 00 2A 37 F9 8A
00 00 2A 37 F9 8B

aditional i found that in the Hex codes ........ for me its a Language i dont speak ..... but may someone else understand it

Reads vender info and prints out........Calculating the checksums according to the specified file.......Unable to get Mac settings, will generate random ones while booting up.......... MAC%d: Empty or invalid checksum....failed to parse vender info, error 0x%x...[-f FILE] [-s].vender.[-f FILE].cksum./vender.SYNO!!!!. Serial: .SN=.CHK=.sn=%s.%s..Empty or invalid checksum...%02x.macs=.%s.,. MAC%d: %s.. Custom Serial: .%x./grub_cksum.syno. Checking file [%s]....Encrypted: .Failed....Passed..file.Specify vender file to read..FILE.show.Show the info..Specify chksum file to read...LICENSE=GPLv3+..........................extcmd.syno...symtab..strtab..shstrtab..rela.text..rela.rodata..rodata.str1.8..rodata.str1.1..data..module_license..bss..moddeps..modname

I can Send more valid samples but i dont want to Post them open here in the Forum .

Can you help us with this Problem ??

Thank You

Thomas and Ray

[The Robman]

I'm sure there are people that know about this stuff, but I've not done anything like this before. When I crack a checksum, it's part of a remote control signal and I've got 20 or 30 samples to work with.

[TN-Notebooks]

I have send more Samples to your Email
and can get lots more.

Because thats valid combinations with checksums i dont wanted to post them visible for all in the Forum.

Can you try if you have enough Samples ?

[The Robman]

I don't see what harm it would do to post them in the forum. What I would be looking for is loads of examples of data with valid checksums, then the case where you have new data and are trying to find the checksum.

The advantage of posting it in the forum is that any of the experts can jump in, as I don't know if/when I will have the time to do it.

[TN-Notebooks]

That are Datas of Customer Units -
I am not allowed to Post that Informations in Public .

I have to be serious with Datas of others.

[The Robman]

The kind of checksums that I normally crack are simple ones using SUM or XOR, you're probably dealing with more complicated ones here. There are a couple of guys here that might be able to help, but it's probably not me.

Best I can suggest is that you post the data in a text file and load it up here, then delete it when we're done.

If that doesn't work, then you probably need to find alternative help with this.

[TN-Notebooks]

Thank you Robman

If anyone wants to try to find the Solution i can send Additional Dataset by PM or Mail.
I realy can get a lot of Trouble if i Post it Public.