Issue
Maintaining device uptime and ensuring data integrity is critical. This article explains the Device Firmware Upgrade (DFU) process, the meaning of “nosync”, and how we’re enhancing system reliability.
Product Line
EcoStruxure Building Operation
Environment
EBO version 5.0, 6. and later
Cause
What Is “nosync”?
Introduced in SBO 1.5, the term “nosync” indicates an incomplete shutdown, which may result in data inconsistency. Devices in this state can be recovered using the DFU process.
What Is the DFU Process?
The Device Firmware Upgrade (DFU) process is a standardized recovery method that restores devices even when system data is corrupted—essentially reviving a “bricked” or “nosync” device.
Instead of booting from internal firmware, DFU allows the system to boot using data sent via USB.
Common use cases:
- Downgrading to an earlier software version.
- Recovering from failed shutdowns to restore functionality.
How Our Devices Store Data—and Why Proper Shutdowns Matter?
Unlike traditional computers, Automation Servers use eMMC memory for continuous data logging. The smallest writable unit is a 4096-byte block. To reduce wear, we use write caches that temporarily store data before writing it permanently.
A proper shutdown ensures all cached data is safely written. Interruptions can cause data loss due to:
- Power Failure: If power is lost before the backup capacitor completes the write process.
- Linux Kernel Crash: Prevents proper data management and shutdown.
Resolution
Improving System Reliability with EBO 7.0
In EBO 7.0 and later includes a major reliability enhancement. The Automation Server will now perform a smart check of its last shutdown status. If an improper shutdown is detected, the system automatically runs the Linux fsck (file system consistency check). This helps determine whether a “nosync” state is truly warranted, reducing false reports and improving reliability.
This enhancement has also been included in EBO versions 5.x and 6.x via hotfixes:
