Here is what I did.
Copied the synoboot.img on my QNAP share
Logged into QNAP via SSH
Captured USB and MAC info for future reference via. lsusb -v and ifconfig (saved to file to local PC)
Copied the synoboot.img onto the DOM flash which was on /dev/sdx ... confirm location with fdisk -l (synoboot is 50MB and /dev/sdx is 512MB so there's plenty of space)
dd if=/share/public/synoboot.img of=/dev/sdx bs=512
(Did not need to use extra.lzma)
Reboot and interrupted GRUB
Generated SN on the website as described in the installation FAQ on this forum
Entered the pid vid sn mac1 mac2 as described in the installation FAQ on this forum
Continue boot, switch to GUI and install DSM as per Synology normal install
So far everything that I need is working nicely.
Things that do not work:
Embedded LCD on the QNAP HW ...it was stuck in "Booting" message so I've just disconnected the cable from the display as I really don't needed and did not want the display to burn out eventually. ....just a cosmetic issue, I don't care. You can probably get it working using https://github.com/bkram/qnapdisplay
LEDs above each individual HDD ...just a cosmetic issue, don't care
Things that I've not tested and I can't confirm that work:
External eSATA ports
