C-8 database corruption after update

My C-8 hub went into a corrupt-database state after a platform update (2.5.1.183 → 2.5.3.123) and I’ve been unable to recover it. I’d appreciate help.

Problem
Immediately after the update, the hub reports a corrupted database and the main interface (8080) is inaccessible. The Diagnostic Tool (8081) is fully reachable.

What I’ve tried, all unsuccessful

  • Rolled the platform back to the previous version (Restore Previous Version) — still reports corrupt database. I've done most of the steps below at 2.5.1.183. I've made no attempt to upgrade after the downgrade.
  • Soft reset followed by restore from several different local backups (including oldest) — each restore returns to the corrupt-database state
  • Soft reset allows me to initialize the device at least. All pages come up but there are no devices/etc. Radios are still paired but I don't think that matters.
  • Restored a backup while in Safe Mode - no change
  • Full power cycle (unplugged at the wall) - no change
  • Tried downloading backup and loading from laptop AND loading directly from the local backups screen
  • I cannot reach Settings (or anything else) after restoring backup

Current state
After a soft reset, the hub boots cleanly on the empty database and is responsive. As soon as any local backup is restored, it returns to corrupt. I have 12 backups going back to September.

Could anyone advise on other possible steps to restore my configuration? My device list is large, so a manual rebuild would be a significant, soul-crushing loss.