The JFFS partition is a part of the routers NVRAM storage device. It is used internally by the router and isn't just 'file storage'. It can't be plugged in or removed either.
The JFFS needs to be fully formatted to remove any previous settings/files that are not appropriate or applicable for the new firmware.
For Skynet, copy your whitelist and blacklists in a safe place. And after doing a fresh Skynet install, import them then.
Are you using OpenVPN or a commercial option? Either way, recreate from scratch is my recommendation. Too many changes (to the VPN options) from your old firmware to the new.
You can import/export the reservations, you can search for those commands/scripts, but you won't see them via the GUI anymore (I'm pretty sure about that). Again, a screenshot or two and configured manually is much preferred if you want the same as you have now.
When you clear nvram via manual methods like wps reset isn't the jffs reformated at the same time?
I would like to believe it is, but experience shows it isn't always the case.
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