UHF-Satcom.com - BT Voyager 2091 firmware version 3.29u                                                                                (17/02/2012 22:30:15 -0000)

Following on from previous firmware versions for the BT Voyager 2091 ADSL model, which allow it to be used with other ISP's, here is the latest available firmware for it. BTW update your device at your own risk. It worked on two devices here used for testing, but this does not mean it will work on your device.

As can be seen from the above image, a 'memory size' line has been added to the device information page. There are some other enhancements that you can read about at the Dynalink website. (http://www.dynalink.co.nz/sm/firmware/rta1025w)

The firmware was modified in a similar way to that mentioned at corz.org. Although some of the info relating to checksums is not correct on that page. The actual check sum details are as follows:

Bytes 0 to 236 are the file header of which bytes 216 to 219 are the checksum for the data part which
is at bytes 256 to EOF. To calculate the checksum, first you must make the CRC32 of bytes 256 to EOF, 
you'll get something like 3A63B72E - convert it to binary, flip the bits then convert back to hex.

CRC32	3A63B72E	00111010011000111011011100101110
flipped	C59C48D1	11000101100111000100100011010001

Using some hex editor like Hex Workshop, over type bytes 216, 217, 218, 219. Next make a CRC32 of bytes
0 to 236 and use the same bit flipping method as above. Then over type bytes 236, 237, 238, 239. Once you have 
done this and saved the firmware image, you are ready to flash your router.

Use the html admin interface to do this.

CRC32	8A7C6FE0	10001010011111000110111111100000
flipped	7583901F	01110101100000111001000000011111

See the picture below for the byte locations.

The firmware used before the update was:

Firmware:  3.28q
ADSL2+ :  A2pB021.d17m
Wireless :  3.91.41.0

and after the update it changes to:

Firmware:  3.29u
ADSL2+ :  A2pB021g.d19b
Wireless :  3.91.41.0  

The firmware file for version 3.29u can be downloaded here. The MD5 for the firmware image in the RAR is a069e6a3fb5dd1f894fd893661bb5d88