HP Apollo DN5500 disk and sysboot

I am trying to salvage a nice Apollo DN5500 server. Unfortunately I had to swap the original Maxtor ESDI 760 HD - it makes a clunky noise - for a lower capacity Micropolis and I have some difficulties to reinstall DomainOS software. The system starts under service mode. It can read a bootable tape and install the mini DomainOS software but it cannot boot DomainOS directly from the hard disk ... it dies with an "Error: sysboot not found" What I've done ... in service mode, with a 10.3.4 boot tape inserted, ) go ... goes to HP logo and login or ) sh runs a text shell ... I was delighted ... but now if I shutdown and reboot the system in normal mode, it passes the tests ok but fails to start the base OS complaining about "sysboot not found". Same result in service mode if I do a > re and > ex domain_os. Considering that it boots fine from a tape, I assume that the sysboot is not a eprom program and that it has been erased by formatting the drive. Does anybody know how to install the sysboot. Does it have anything to do with the 40KB file copied from the tape to //nodeXXX/sysboot on the hard disk? Kind regards, Aro