First off, you’re not going to get rich from mining on your old unused BeagleBone black and you’ll arguably only lose money, but for about 10W of power, you might be able to mine some low difficulty altcoins that are cpu or gpu only. I am currently mining Galactrum on mine using CPUminer-multi.
Thanks to its wide array of miners, you can use cpuminer-multi to mine a lot of altcoins, so lets get into compiling it.
Its 2019 and your Raspberry Pi is sitting in the corner. You haven’t used it much since your last project and you are ready to do more with it. Why not mine a CPU only or low difficulty coin? Sure you won’t get rich, but you’ll have some crypto to trade around and learn about compiling miners and how to use exchanges and how to use mining pools. The Pi also uses a very small amount of power.
Magi coin uses a POW/POS system but with a bit of a twist. As they put it “MAGI concentrates on global energy savings when maintaining its blockchain system. MAGI aims at worldwide mining based on, for example, mobile devices. MAGI’s PoW with difficulty dependent mining rewards applies a limit to the total network hashrate, where huge amount of computational power for mining is no longer necessary”
This makes it the perfect target for mining with that old Raspberry Pi you just have lying around.