When looking for SGOS version 7.3.5.1 on the Broadcom support portal,
it is not available for download.
SGOS 7.3.5.1 was removed from the Broadcom support download portal and
replaced with SGOS 7.3.5.2 due to bug SG-28388:
SG-28388 - The appliance experiences a restart when upgrading server
connections to HTTP/2.
SGOS 7.3.5.2 contains a fix for bug SG-28388.