I did the downgrade as well. Any version of the firmware 3.0 or above couldn't maintain a stable network connection on my Max 2. V2.2.2 is much better. The newer firmware download links are all dead so 2.2.2 is the latest you can get which is pre V3.0 (that I have found, at least).
Many thanks to @Galunid for posting the link.
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