Rockbox Development > New Ports
Creative Zen Vision:M
Hitman2k7:
--- Quote from: mcuelenaere on July 06, 2007, 04:46:32 PM ---If you just change the checksum, nothing is changed in the firmware itself but you could see if the transfer would succeed with an altered checksum.
--- End quote ---
Can you tell me how i can change the checksum?
mcuelenaere:
--- Quote from: Hitman2k7 on July 07, 2007, 11:04:56 AM ---Can you tell me how i can change the checksum?
--- End quote ---
The easy way: download http://www.verzend.be/v/114342/ZENVisionM_30GB_PCFW_L21_1_62_02_nk_altered.rar.html
(its checksum has been changed)
The DIY way: use a hex editor and go to the last 20 bytes: these contain the checksum, change them to whatever you want, it makes the checksum incorrect.
mcuelenaere:
Damnit, the player checks the checksum :(
First, I tried upping a modfied file, which gave me:
SendObject: Operation failed, response = MTP_RESPONSECODE_ACCESSDENIED
Then I upped the correct one, which gave me:
SendObject: sent 21767736 bytes, response = MTP_RESPONSECODE_OK
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 ...
P.S.: XP users trying to use DirectMTP: http://www.verzend.be/v/6860021/DirectMTP.rar.html
Hitman2k7:
Right, checksum check is made by the player.
I modified the updater to transfer a different nk.bin than the one which comes with the updater.
It gives an Update failed error after transfering the file :(
wantondstrction:
Well, alas, I can't get an altered nk.bin onto the player by those means. I can still get the official nk.bins on there that way though. Every time I try I get an Access Denied error. I'm gonna keep plugging along.
I knew it was too good to be true, but it seemed positive when the official one worked.
I even tried formatting my player to limit the amount of objecthandles that popped up, but none of the objecthandles given matched firmware remotely.
At this point, I'll state some of the obvious.
1. The player itself does the checksum
2. The official firmware loader is relatively pointless. (It's more or less just a long command line to interact with the player doing the directMTP functions.)
3. Mcuelenaere, you're right. I tested that theory out by altering different parts of the code on a few different nk.bins and some failed noticeably quicker than others.
Has anyone tried removing the last 20 bytes of an nk.bin altogether?
Edit: Oddly, I managed to get an altered nk.bin onto the player. I had a program crash and it quit watching what file formats were being copied onto the player. It hasn't done anything and hasn't upgraded the firmware or done anything with it. It's just there. All I did was copy and paste during a huge transfer after a program crash. (reloading my music after formatting)
It's chilling next to devlogo.fil and so on. It's not that this means much of anything, but it's further than I've managed to get to date. I'm looking into isolating exactly what happened.
(I realize this doesn't help with the checksum)
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