Troubleshoot cEdge Upgrade "Not Enough Space in SDWAN Installer Filesystem"

Introduction

This document describes the issue related to Cisco Edge Router upgrade activities blocked with config-register 0x8000 and 0x0040 flags.

Issue

On Cisco Edge Router devices, software upgrade activities can fail with either one of these errors:

• Executing device action Software Install
• Installing software image
• Cannot determine current boot partition on device <system-ip>

SDWAN Installer Space Check: Not enough space in SDWAN installer filesystem. SDWAN installer filesystem size - 396672 Kilobytes, Available space - 217894 Kilobytes, Required space - 10055522 Kilobytes. 

In the second log, the required space value (10055522 Kilobytes) is far larger than the supported installerfs size and therefore invalid for this condition.

Environment

• Platform: Cisco Edge Router (cEdge)
• Mode: Controller mode (SD-WAN)
• Scenario: Software upgrade or software install workflow
• Condition: Configuration register includes 0x8000 or 0x0040

Resolution

• Schedule a maintenance window and obtain change approval.
• Ensure console access is available for the router.
• Back up the current running configuration.
• Be aware that configuration changes made while the configuration register included 0x8000 or 0x0040 does not persist after reload.

Caution: Reloading a router after changing the configuration register can result in loss of configuration and loss of fabric connectivity. All configuration changes made while the configuration register included the 0x8000 or 0x0040 flags are lost upon reload. The router can fail to connect to the fabric after reload, which can require console access to correct the configuration. Ensure console access is available before you perform this procedure.

Change the configuration register to a standard value such as 0x2102 or 0x3922, which instructs the router to load normally.

configure-terminal
 config-register 0x2102
commit

Verify

Before the Change

Run the command show version | include Configuration to check the current configuration register value.

Here are examples of affected values:

#sh ver | i Configuration
Configuration register is 0x8000

and

#sh ver | i Configuration
Configuration register is 0x2142

After the Change

1. Reload the router during a maintenance window.

2. After the router boots, confirm the configuration register value:

show version | include Configuration

3. Verify the output shows the expected value (for example, 0x2102).

4. Retry the software upgrade and confirm the operation no longer fails with either of these errors:

• Cannot determine current boot partition on device

• SDWAN Installer Space Check: Not enough space in SDWAN installer filesystem

Cause

The issue occurs when either of the config-register flags is set: 0x8000 or 0x0040.

The flags 0x8000 and 0x0040 in the configuration register cause the router to ignore the startup configuration stored in NVRAM.

• 0x8000: Enables diagnostic messages and causes the router to ignore NVRAM contents.
• 0x0040: Causes the system software to ignore the contents of NVRAM.

Those flags were designed for standalone mode, but they have an adverse effect when enabled in controller mode.

Related Content

• Understand Configuration Register Usage on all Routers
• Cisco bug ID CSCwv02836

Revision History

Revision	Publish Date	Comments
2.0	16-Oct-2026	Corrected Tech zone error with numbers
1.0	16-Oct-2026	Initial Release