You will need to have a spare hard drive that you don't mind losing the data on since it will be formatted during these steps.
Be warned that this is a user submitted process that allowed me to successfully (and at least a few other users) get back to an earlier 2.5 ADM version with no loss of data. However, this is or at least not yet an official process.
If you use this process please post a message if it was successful or if it did not work.
From post: http://forum.asustor.com/viewtopic.php?f=97&t=7037
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Sounds like I'm not the only one getting into this problem. So here is what I did to get downgraded
.You will need a spare drive that you can use. Luckily I had one sitting around.
First turn off the NAS and then remove ALL of the drives in the NAS and set them aside. I suggest numbering them in some fashion to remember where they go (not sure it matters but better safe than sorry).
Second, install a new (or empty) drive into the NAS. Your going to have to format this drive and will lose anything on the drive (SO DO NOT USE your current drives).
Third, reboot the NAS. It should not boot and apparently it will jump right over the booting of the storage since the drive is empty.
Fourth, I connected to the NAS from the web interface and went through the initialization process for a single drive. Simply adding a admin password, setting the time, and formatting the single drive.
Fifth, After formatting complete you should be able to get into the ADM interface from the web.
Sixth, Go to the Services app and the tab for ADM. You'll notice there is an option to manually update the ADM release. Since, Asustor does not make it easy to find past ADM releases from there website you will have to figure out the naming for your image file. I did this by looking at the release notes and using the same naming convention. Example, below:
ADM 2.5.2.RCG2 - http://download.asustor.com/download/ad ... 2.RCG2.img
ADM 2.5.1.RB62 - http://download.asustor.com/download/ad ... 1.RB62.img
ADM 2.5.0.RA73 - http://download.asustor.com/download/ad ... 0.RA73.img
Once you've download the image use the manual update to locate the downloaded image and go ahead and update the ADM version. You will get a notice that your are downgrading versions (but heck the current version doesn't work).
Seventh, Let the NAS reboot (with your single drive). Then shutdown the NAS.
Eight, Remove the single drive and replace it with all the drives from before in the order you numbered them.
Ninth, Reboot the NAS and you should be good to go.
Warning, I was already running a 2.5 version of ADM. If you are an early version than I'm not sure this will work.
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