If the unzip process is not done targetting a staging directory (e.g. `/meadow0/Temp/staged-update`), then a power reset during this process will cause a partial update to apply, potentially making the device/app unusable.

[alexischr]

If the unzip process is not done targetting a staging directory (e.g. /meadow0/Temp/staged-update), then a power reset during this process will cause a partial update to apply, potentially making the device/app unusable.

To Reproduce Steps to reproduce the behavior:

1. Begin an app update
2. Wait for the unzip part
3. Press the device's reset button
4. Observe issue

Expected behavior Either the update applies or it does not, atomically.