glad the build has been of use to you...
no need... perfectly valid question...
the best way is to;
- add any extra files you have not added yet to sysupgrade.conf@luci>system>backup>configuration
- upgrade to the lastest (community) build to get the gui backup feature
- use the backup feature provided
- download the file
- flash a new official factory (remove sdcard and full flash)
- boot the new factory image (at 192.168.1.1)
- restore your backup (ip may change if different perhaps reboot)
so given the advice above... likely not...
for advanced users technically you could try 'sysupgrade -n -p -F newfactory.img'... but there will be automatic artifacts in installed_packages.txt... (which wouldn't be a direct problem)