I just tried k3flasher-x86_64.bin from the first post, and when running from my x86_64 linux mint 11, I get this:
./k3flasher-x86_64: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.14' not found (required by ./k3flasher-x86_64)
The version that I built from source code works fine though, and so does the k3flasher-x86.bin (32-bit version) that I downloaded from the first post.
EDIT: I am now making a backup copy of a K3 demo unit, using k3backup.sh
EDIT2: Now flashing 3.0.2 to K3 demo. Preceded ./k3flasher with "time", so I can report the exact time it took to complete... (I did notice that the demo screens stopped advancing after flashing the replacement kernel.)
EDIT3: mmcblk0p1 flashing completed in 107m 11.078s. Now to reboot... Yes, firmware version 3.0.2. I plan to set it to factory defaults after I make backup copies of the user store and persistent user store partitions. Jailbreak time! Then firmware upgrade... 
EDIT4: Factory reset, register to my amazon account, 3G and wifi both work fine. The pastebin now has 3.4 firmware with jailbreak and dev keys pre-installed.