# Halting Unified ISSU During Upgrade Phase

After you stop unified ISSU, you can return the router to the state it was in when you began the unified in-service software upgrade. To roll the router back to its beginning state with the redundant SRP module running the original release, you must perform the following steps to arm the redundant SRP module with the running release:

1. Turn off auto synchronization.
   host1(config)#disable-autosync
2. Specify that the router use the running release when it reboots.
   host1(config)#boot system erx_x-y-z.rel
3. Synchronize the NVS file system of the redundant module with that of the primary module.
   host1#synchronize

   The redundant SRP module automatically reboots because the software release that it is configured to run now differs from the software release it is running.

#### Related Documentation

- Unified ISSU Phases Overview
- Halt of Unified ISSU During Upgrade Phase Overview
- disable-autosync
- boot system
- synchronize