[Info-vax] Help needed booting VAX 4000-200 from Alpha using Infoserver utility

[terry-groups at glaver.org]

I am trying to do a clean install of VMS 7.3 (from the Hobbyist Program) on a VAX 4000-200 (real, not emulated) via my VMS 8.4 Alpha DS10 (emulated via AlphaVM Pro). The 4000-200 has an existing installation of VMS 5.4-3 which is working, so I know that hardware is good. Likewise, the emulated Alpha DS10 has been running for years with no problems.

I am basing this on the documentation at:
https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c04623149

I have configured the Infoserver utility and have MOP enabled on the Alpha, with the Hobbyist "OpenVMS VAX 073 OS.iso" mounted in $1$DKA400:

SERVER::$ RUN SYS$SYSTEM:ESS$INFOSERVER
InfoServer> show service
Service Name         [Service Class] Device or File
-------------------- --------------- --------------------------
VAX073               [ODS-2]         _$1$DKA400:                
%INFOSRVR-I-FOUND, 1 service found.

When I "B/R5:100 EZA0:" on the VAX 4000-200, and give it the ISL_SVAX_073 filename I see the expected:

Network Initial System Load Function
Version 1.2
FUNCTION         FUNCTIONID
1     -        Display Menu
2     -        Help
3     -        Choose Service
4     -        Select Options
5     -        Stop

Entering 3, then 2, then ISL_SVAX_073 at the "Enter a Known Service Name:" prompt returns with "No Services Found."

Entering 3 then 1 for "Find services" returns the expected "# 1  VAX073" service, but selecting 1 responds with "%ISL-F-BADOPEN, unable to locate SYSBOOT" and halts at 000073C4.

The only OPCOM messages I receive pertain to the initial netboot:

%%%%%%%%%%%  OPCOM  20-MAR-2019 15:55:55.39  %%%%%%%%%%%
Message from user DECNET on NODE
DECnet event 0.3, automatic line service
>From node 35.63 (SERVER), 20-MAR-2019 15:55:55.39
Circuit EWA-0, Load, Requested, File = MOM$SYSTEM_SOFTID:ISL_SVAX_073
Operating system, Ethernet address = 08-00-2B-aa-bb-cc

SERVER::$ 
%%%%%%%%%%%  OPCOM  20-MAR-2019 15:56:00.39  %%%%%%%%%%%
Message from user DECNET on NODE
DECnet event 0.3, automatic line service
>From node 35.63 (SERVER), 20-MAR-2019 15:55:56.16
Circuit EWA-0, Load, Successful, File = MOM$SYSTEM_SOFTID:ISL_SVAX_073
Operating system, Ethernet address = 08-00-2B-aa-bb-cc

Any suggestions as to what I might be doing wrong?

I have never used the Infoserver utility on Alpha VMS, but this VAX 4000-200 has no optical drive and a broken tape drive, so I'm somewhat limited in my boot options to get VMS 7.3 installed.