BACKUP/IMAGE in VMS8.4 results in corrupted target

[Gremlinsz]

Build AXPbox from mainline and run it on a RaspberryPi 4 Buster fully updated.

Autocreated a disk in es40.cfg size 1500M. Installed VMS from CD and it has been running fine.

Found that I could create a disk 2000M but not anything larger than 1G. Booted AXPbox from CD and did a BACKUP/IMAGE of the "old" boot drive at 1500M to the "new" drive of 2000M. Backup completed fine and I could boot from the new disk, but part way through it fails with:

AlphaServer ES40 Console V7.3-1, built on Feb 27 2007 at 12:57:47
P00>>>sho dev
dqa0.0.0.15.0 DQA0 RZ27
dqa1.1.0.15.0 DQA1 RZ27
dqb0.0.1.15.0 DQB0 ALPHA084 .ISO
dqb1.1.1.15.0 DQB1 RZ28
dva0.0.0.1000.0 DVA0
ewa0.0.0.4.0 EWA0 08-00-DE-AD-E5-40
P00>>>b dqa0
(boot dqa0.0.0.15.0 -flags 0)
block 0 of dqa0.0.0.15.0 is a valid boot block
reading 1230 blocks from dqa0.0.0.15.0
bootstrap code read in
base = 200000, image_start = 0, image_bytes = 99c00(629760)
initializing HWRPB at 2000
initializing page table at 1ff56000
initializing machine state
setting affinity to the primary CPU
jumping to bootstrap code

OpenVMS (TM) Alpha Operating System, Version V8.4    
© Copyright 1976-2010 Hewlett-Packard Development Company, L.P.

%SYSINIT-E- error mounting system device, status = 0072841C

**** OpenVMS Alpha Operating System V8.4 - BUGCHECK ****

** Bugcheck code = 0000036C: PROCGONE, Process not in system
** Crash CPU: 00000000 Primary CPU: 00000000 Node Name: API1
** Highest CPU number: 00000003
** Active CPUs: 00000000.00000001
** Current Process: SYSINIT
** Current PSB ID: 00000001
** Image Name:

**** Starting compressed selective memory dump at 19-NOV-2021 14:35...

I have created a new 2000M disk and backup-up to it several times, same problem... booting from the 1500M disk works without problem.