I see the “unclassified error” too, I am not particularly worried at the moment. My explanation (maybe completely wrong) is that something has changed in the block format with the recent version for the zeronet and some nodes (not ours) are still running an old version
“too few connections(0)” is normal, as long as it happens only from time to time. If you keep the node running long enough, it will establish more and more connections and the chance of getting (0) becomes less likely. Keep in mind also that there are few nodes running on the zeronet.
Updates, good question.
I’ll try to keep supporting Tezos for RPI3 with the precompiled version through all the stages, alphanet->betanet->mainnet, unless at some point I get a red card from the TF. You are right the zip file is just that, basically I save you the trouble of compiling it by yourself.
But if you are planning to run a node on the mainnet you should definitely give it a try, please do it, I can help you out, and please feel free to contribute to the wiki page (it is open access).
To get started with the compilation, in the wiki page there is a link to old notes [a], have a look at the steps
to compile Tezos (second part of the notes), however because they are somehow outdated, before jumping into the real work, have a look also at page [c] (unpolished instructions) and replace whatever is in the old notes[a] with the updated instructions in [c]. I know it is far from ideal, but keep re-writing detailed instructions that would become outdated quickly is not worth the effort right now.
Anyway if you get stuck somewhere in the process let me know…