It is possible to upgrade to some versions of Nodegrid OS without going through the recommended intermediate versions of NG v4.1.6 or v4.2.4.  This article applies to systems running the following versions:

• NG v4.1.7 or newer
• NG v4.2.5 or newer
• NG v5.0.x

There will not be any issues with this situation until trying to upgrade to a version which requires a larger partition.  At that point the upgrade will fail with a 'No space left on device' error.  In most cases the system will reboot to the starting version.  Occasionally the space error will result in boot failure.  If the system is no longer able to boot, the drive will need to be formatted using How to format the hard disk while installing Nodegrid OS to restore normal functionality.  Because of this risk, we recommend checking the partition size prior to upgrading.

How to check the partition size:

1. Log into the CLI as admin
2. Access the root shell using: shell sudo su -
3. Get the current partition data using: df -h

1. Look for the line where / is listed in the Mounted on column
2. The name listed for the Filesystem column may vary
3. Read the value in the Size column
4. The line looks like this:

Filesystem      Size  Used Avail Use% Mounted on

/dev/sda3       1.4G  1.3G   71M  95% /

4. If the / partition size shows 2.6G, the partition size is already increased and the unit can upgrade to any newer version.
5. If the / partition shows as 1.4G (as in the example above), please apply one of the following solutions:

Note: If the starting version is NG v4.1.7 or newer, upgrade to NG v4.2.4 before upgrading to the desired version.  No other special action is required.

Warning: Manual re-configuration will be required if the starting version is newer than the final target version.  To avoid this, utilize these steps when upgrading.

• Warning: the downgrade process will restore the system to factory defaults unless a backup is present for the chosen version.
• You may choose to downgrade to an older NG v4.2.x version and then upgrade to NG v4.2.4 to invoke the size increase.

• This can be helpful when a backup configuration is present for the older version.
• The installers for NG v4.2.4 contain tools which will increase the partition size.  This is not available on any other supported version.

• We recommend using NG v4.2.4 since the only other available option is to use the NG v4.1.6, which is EoL.  

1. Save a copy of the configuration using System :: Toolkit :: Save Settings
2. Downgrade to NG v4.2.4 
3. Reconfigure the system so it can be accessed for upgrading
4. Upgrade to the newer target version
5. Apply saved configuration using System :: Toolkit :: Apply Settings

Install from USB with format option:

• Warning: The format process will erase all data including configurations and logs on the drive.
• NG v5.2.x and v5.4.x offer the option to format the drive when booting from USB.

1. Create the USB media for NG v5.2 or newer using:  Nodegrid Boot from USB media article
2. Save a copy of the configuration using System :: Toolkit :: Save Settings
3. Install using the created USB media: How to format the hard disk while installing Nodegrid OS
4. Apply saved configuration using System :: Toolkit :: Apply Settings