Rockbox Development > New Ports
Creative Zen Vision:M
Hitman2k7:
Well I also got an nk.bin on my players hd by changing the Formatcode to undefined. But the player doesn't do anything with it unless changing the formatcode to firmware but that's as far as i know not possible.
--- Quote ---GetObjectInfo: received ObjectInfo:
Format code = MTP_FORMATCODE_UNDEFINED
Protection status = MTP_PROTECTIONSTATUS_NONE
Compressed size = 21767736
Thumbnail format = MTP_FORMATCODE_NOTUSED
Thumbnail size = 0
Thumbnail width = 0
Thumbnail height = 0
Image width = 0
Image height = 0
Image bit depth = 0
Parent obj handle = 0x0
Association type = MTP_ASSOCIATIONTYPE_UNDEFINED
Association desc = 0
Sequence number = 0
File name = nk.bin
Capture date =
Modification date =
Keywords =
--- End quote ---
The red thing has to be 0xb802 (UNDEFINEDFIRMWARE) for the player recognizing it.
iSE:
--- Quote from: mcuelenaere on July 07, 2007, 11:32:10 AM ---A small comment I noticed, my ZVM gave that responsecode pretty fast; so it must be computing the checksum while it is receiving the firmware, cause computing the SHA-1 checksum even on a 1,0Ghz comp takes 10 to 15sec ...
--- End quote ---
Just to check, are you sure that the player actually calculates the checksum, or just compares it with a static one? try altering the nk.bin but leaving the checksum the same. Does that fail? I know theres a 99.9% chance it will but it mite be worth eliminating as a step to discovering when the checksum is calculated by the player. (start, middle, during, end etc)
Hitman2k7:
--- Quote from: iSE on July 08, 2007, 05:18:52 AM ---try altering the nk.bin but leaving the checksum the same.
--- End quote ---
That's impossible. The checksum completely changes even if you change only 1 byte of the file.
But how does the player know if the file is an official one? I mean they all have different checksums and creative has no influence on them...
aegis:
--- Quote from: Hitman2k7 on July 08, 2007, 05:45:53 AM ---
--- Quote from: iSE on July 08, 2007, 05:18:52 AM ---try altering the nk.bin but leaving the checksum the same.
--- End quote ---
That's impossible. The checksum completely changes even if you change only 1 byte of the file.
--- End quote ---
I think iSE knows it. :P
What he says is: are you sure the player actually calculates the checksum? Maybe it's only comparing some strings here and there? And if it calculates the checksum - on which stage is it done? Is it calculated for the whole code? etc. etc.
--- Quote from: Hitman2k7 on July 08, 2007, 05:45:53 AM ---But how does the player know if the file is an official one? I mean they all have different checksums and creative has no influence on them...
--- End quote ---
Again: are you sure with your assumptions? :)
Certainly, the Creative must have the influence upon them - unless they stuff their code with a large pile of rubbish by design just to fit some arbitrary checksum - however I wouldn't bet it would really work.
So, if altering the code and putting the right checksum (again, are you sure? :) ) in the end does not work, it means for me there must be some duplicate of the checksum in the code. Maybe it's split on two or more strings, maybe it's *very simply* encrypted (like add 1 to a char, or so on), maybe it's something more sophisticated, some version code or whatever - I don't know - but there must be some way for the program to validate the update and say "sorry, it's not ours".
iSE:
Agreed. There are a lot of assumptions flying around and a lot of progress has been made, however, specifics are needed and facts should be seperated from supposition.
What if we just run through what is known, what is assumed to be true, n what there is a vague suspicion of? This could then help to recap where everyone is up to and we can finally update the wiki lol.
mcuelenaere, im trying to make sense of this template for the 010 editor that I_e made on the epizenter forum. However, using the latest firmware: ZENVisionM_60GB_PCFW_L21_1_21_02e, I do not seem to be able to get the same results or locate the checksum in nk.bin. Does it only work with the 30GB version?
What I am hoping to try is to remove the NULL part containing the checksum and then calculate various hashes from the rest of it to determine which checksum the NULL block matches. Since I am assuming the checksum would not be calculated from the checksum itself. What if we get together a list of the different checksums, that mite help to calculate the algorithm?
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