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Code Issues Releases Wiki Activity

Added images to assets folder, fixed paths in posts.

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Markus Birth 2014-05-16 09:55:29 +02:00
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commit 07a59e63dc
3 changed files with 2 additions and 2 deletions
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_posts/2009-02-02-asus-wl300g.md
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@ -36,8 +36,8 @@ So there has to be some sort of checksum which tells the router whether the firm
Therefore I compared the two files `dd-wrt.v23_asus.trx` and `dd-wrt.v23_generic.bin` and voilà: Besides the few bytes at the end of the file, there were 4 additional bytes different at position `0x08`. This HAD to be the checksum. The remaining question was, from which bytes it was calculated. Since the seemingly compressed data began at `0x28`, I tried from there to the end and used [Hex-Workshop](http://www.hexworkshop.com/) to calculate different checksums, but nothing matched what was in these 4 bytes. The next try was from `0x10` but also no match. Then I tried starting directly after the checksum in the header, from `0x0c` and bang: The CRC32 checksum matched that in the header. Therefore I compared the two files `dd-wrt.v23_asus.trx` and `dd-wrt.v23_generic.bin` and voilà: Besides the few bytes at the end of the file, there were 4 additional bytes different at position `0x08`. This HAD to be the checksum. The remaining question was, from which bytes it was calculated. Since the seemingly compressed data began at `0x28`, I tried from there to the end and used [Hex-Workshop](http://www.hexworkshop.com/) to calculate different checksums, but nothing matched what was in these 4 bytes. The next try was from `0x10` but also no match. Then I tried starting directly after the checksum in the header, from `0x0c` and bang: The CRC32 checksum matched that in the header.
![Hex Workshop Screenshot](hexworks.png) ![Hex Workshop Screenshot]({{ site.url }}/assets/hexworks.png)
So I calculated the CRC32 of my modified file and changed the header - and now I could upload the DD-WRT file using the normal firmware upgrade of the original firmware. After installing v23, you can easily update to v24 using the DD-WRT web interface. So I calculated the CRC32 of my modified file and changed the header - and now I could upload the DD-WRT file using the normal firmware upgrade of the original firmware. After installing v23, you can easily update to v24 using the DD-WRT web interface.
![DD-WRT Version Info](ddwrt.png) ![DD-WRT Version Info]({{ site.url }}/assets/ddwrt.png)

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