I ran into the same issue with the E6410 - I solved it by going into the BIOS settings and chanings the SATA configuration from 'RAID On' to AHCI.
After that I was able to boot with a USB or floppy drive without issue..
"RAID ON" is never going to work with the current products - the BIOS simply does not expose the standard interfaces it seems with that mode enabled.
More informational, than a question. I had my hopes up for EEPC 5.2.9 and it's mention of fixes for RAID On and the Dell E2 series. I've confirmed that although EEPC and also Wintech seem to function, SafeTech does not.
Momma says RAID On is da devil.