flash it the way you flash any image, just change the name to usb_update.img and flash.
by the way, this procedure worked for me only with sif images, nlb didnt.
for enigma2 installation:
1. Format your USB flash pen under windows (should be more than 1GB for enigma2)
2. Insert your USB stick while box is on
3. Open KCC (http://www.denktenk.com/modules/wfdow ... file.php?cid=35&lid=1206)
4. Change the IP and user/pwd for both telnet and ftp and go to Experts tab.
5. format your flash pen with KCC in ext2/ext3 format.
6. Turn off your box, remove the flash pen, boot again, after full boot insert the usb flash pen again
7. FTP to the box and transfer the e2 image archive (tar.gz) to /mnt/usb/usb0
8. Telnet to your box
9. execute cd /mnt/usb/usb0
10. execute tar -xzf filename.tar.gz (case matters) and wait till process is done
11. execute sync
Now if you have already installed your multiboot, you can run your enigma2.
turn off the box, boot again and while on the 8888 press and hold 5 on your remote control till "Multi" is shown on the front display.
wait till e2 completes booting, first time takes much more time to boot.
You will need to replace your satellites.xml at /etc/tuxbox/ and reboot if you cant find all of your satellites.
Dont boot into DGS based image while the usb pen with e2 is inserted as it might get formatted.
Just a note for you, internal card readers dont work with enigma2 (driver not ready).
if you want to be able to record, you will have to use a large capacity flash pen/hdd and make 2 partitions (1gb for e2 and the rest for recordings)
i recommend the latest pkt sif image as it works well for me