Loading the Duokan alternate firmware for Kindle

Duokan is a Chinese, alternate firmware for Kindles, which seems to be optimized for Chinese characters. On the Kindle 3, it handles PDFs much better than the original Kindle PDF viewer, and also has an internal pdf2txt converter to enable simple PDFs to be read as normal reflowing text.

The installation instructions on various English-language websites offer a whole range of suggestions, many of which did not work for me. So here is how I installed Duokan on a Kindle 3 (Keyboard, 3G) with firmware 3.4.

  1. Go to the Duokan website and click the orange button at the bottom of the Kindle section. This takes you to a BBS in Chinese. Find the Kindle 3 section and snoop around with your pointer until you find the link to http://www.vdisk.cn/. At the bottom of the page are blue boxes for different download options. Try these until you get a download. The version I got was (k3)xKindle_2013-01-25.20781.rtm.zip
  2. Unzip the file, and copy (recursively) DK_System to the root directory of the Kindle (as mounted via USB).
  3. Look in the directory that contains (for 3.2.1 and 3.3 version update) in its name. There are three .bin files. They may not show up under some file browsers, and you may not be able to select the directory in a terminal due to the Chinese characters in the directory name. A trick is to use the inode numbers: ls -i to find the inum of the dir, and find . -inum <inum> -exec ls -l {} \; to view the files. Copy the files (in my case update_duokan_0b006.bin, update_duokan_0b008.bin, update_duokan_0b00a.bin) to the root directory of the Kindle. Unmount.
  4. Switch off wifi. In Menu -> Settings -> Menu, you should see the Update option darkened (selectable). Select this. Wait a long time while the Kindle says it is updating. After this, a terminal screen appears and says it is installing DuoKan. It then reboots and you get the Kindle reboot screen for a bit before the DuoKan splash appears. Select Q for DuoKan and it will load up DuoKan.
  5. The original settings are all in Chinese. Select Menu -> System Settings -> D (Language) and select the penultimate option (English). Then select Menu -> System Settings -> E (IME) and select the final option (Latin).

Duokan should now be running. You will not see your Amazon books (Menu -> System Settings -> B to switch to normal Kindle for that), but you will see content you added (EPUBs, PDFs, etc). For reading 2-column PDFs, I suggest selecting Menu -> Cut Edge -> Split option 3. Two- and three-column PDFs may be garbled with Menu -> Enable Smart Layout, depending on how the PDF columns are encoded in the PDF file. All in all, it works great, and being able to read ePubs is nice (although Calibre’s ebook-convert can convert EPUBs to MOBIs on the desktop).

See also