SCSI Tape boot

Hi all, I've created a .TAP file using E11 which contains a bootable RT-11 image. I wrote this using st.exe to a DAT tape via my Adaptec 2940UW. E11 boots this fine, no matter the type of the MU0 device within the simulator. But if I try booting it using a CQD220A/M/T in /T mode, I get a "?BOOT-U-I/O error" which seems RT-11 enough to make me think it is actually trying to boot MSBOOT.BOT. The .TAP file was creating using E11's TU81 emulation and MUB.COM within RT-11 V05.06. A console log follows: KDF11B-BE ROM V0.9 1024KB MEMORY 9 STEP MEMORY TEST STEP 1 2 3 4 5 6 7 8 9 TOTAL MEMORY ERRORS = 0 CLOCK ENABLED 1024KB MEMORY KDF11B-BE ROM V0.9 CLOCK ENABLED ERR 12 NON-EXISTENT CONTROLLER Use CTRL/Z to return to MAIN MENU 173402 @17760406/005500 123456 @/001000 100 @5000g SCSI UTILITY PROGRAM 2.0 DISK TAPE 1 = 772150 A = 774500 2 = 760334 B = 760404 3 = 760354 C = 760444 4 = 760374 D = 760504HELP 5 = 760340 E = 760544 6 = 760344 F = 760410 ARROW" or "DOWN ARROW" to select function 7 = 760350 G = 760450 8 = 760360 H = 760454u SELECT CSR ADDRESS b MAIN MENU: CSR = 760404 1 = BOOT DRIVE 7 = ADDITIONAL SCSI COMMANDS SELECT OPTION : 1 BOOT DRIVE NUMBER <0 TO 7>: 0 BOOT MU0 . ARE YOU SURE? y WAIT... ?BOOT-U-I/O error ? With DEV0 being: DEV0: MU0 SCSI ID 0 LUN 0 HP C1537A L708 Disc ON,Sync ON,3-Density ON,Buffer ON, Anyone have an idea what I could do to further this along? regards, Sander Reiche