I want to update a Netgear R7800 from 17.01.5 to 18.06.1. I know that I will need to do it with a 'factory' image via TFTP because the partitioning has changed. This means I will lose all settings.
Can I make a config backup before the upgrade and restore that after the upgrade? I am not sure why it would be a problem but just wanted to double check.
Generally a config from 17.01 can be used by 18.06. No guarantees, but at the very least it can guide you to crafting an new configuration if there are incompatibilities.
sysupgrade can simplify making a config backup:
$ sysupgrade
Usage: /sbin/sysupgrade [<upgrade-option>...] <image file or URL>
/sbin/sysupgrade [-q] [-i] <backup-command> <file>
upgrade-option:
-f <config> restore configuration from .tar.gz (file or url)
-i interactive mode
-c attempt to preserve all changed files in /etc/
-n do not save configuration over reflash
-p do not attempt to restore the partition table after flash.
-T | --test
Verify image and config .tar.gz but do not actually flash.
-F | --force
Flash image even if image checks fail, this is dangerous!
-q less verbose
-v more verbose
-h | --help display this help
backup-command:
-b | --create-backup <file>
create .tar.gz of files specified in sysupgrade.conf
then exit. Does not flash an image. If file is '-',
i.e. stdout, verbosity is set to 0 (i.e. quiet).
-r | --restore-backup <file>
restore a .tar.gz created with sysupgrade -b
then exit. Does not flash an image. If file is '-',
the archive is read from stdin.
-l | --list-backup
list the files that would be backed up when calling
sysupgrade -b. Does not create a backup file.
It's just that there are changes to the partitions between 17 and 18 and so you can't do a normal sysupgrade, it needs to be a completely fresh factory install.
If there are references to partitions in the config backup that could pose a problem. I don't believe there are, though. Just wanted to check.
If you want to be experimental, you can first flash my 17.01 branch "large-flash" build (from the community builds sections) and then restore the 17.01.5 settings there. That "large-flash" 17.01 build has the new partition structure, so you can then sysupgrade normally from it to 18.06.
OK, I have upgraded using the TFTP method to the factory.img, restored the config backup once it was up and so far, after two hours and a lot of testing, everything seems to be fine.