There’s fairly a number of gadgets in the marketplace that comprise a Raspberry Pi as their core, and after changing into a proud proprietor of a photo voltaic roof, [Paolo Bonzini] has discovered himself with an Entrade ENR-DTLA04DN datalogger which – let’s simply say, it had a few of the indicators, and at FOSDEM 2023, he instructed us all about it. Put in beneath the promise of local-only logging, the datalogger gave away its nature with a Raspberry Pi logo-emblazoned energy brick, a spec sheet equivalent to that of a Pi 3, and a MAC handle belonging to the Raspberry Pi Basis. That spec sheet additionally talked about a MicroSD card – which ultimately died, prompting [Paolo] to take the duvet off. He dumped the defective SD card, then changed it – and put his personal SSH keys on the system whereas at it.

At this level, Entrade not provided gadgets with native logging, solely the choice of cloud logging – free, however just for 5 years, clearly not an possibility in the event you like your house cloud-free; the native logging was not flawless both, and thus, the system was price exploring. A fast peek on the filesystem netted him two giant statically-compiled binaries, and strace gave him a technique to eavesdrop on RS485 communications between the datalogger and the photo voltaic roof-paired inverter. Subsequent, he dug into the binaries, accumulating info on how this system did its work. Beforehand, he discovered that the system supplied an undocumented API over HTTP whereas linked to his community, and evaluating the API’s workings to the information contained in the binary netted him some good outcomes – however not sufficient.

The primary binary was recognized to be Go code, and [Paolo] exhibits us a walkthrough on tips on how to reverse-engineer such binaries in radare2, with a small assortment of methods besides – as an example, grepping the output of strings for GitHub URLs in an effort to discover out the libraries getting used. Ultimately, having reverse-engineered the protocol, he absolutely rewrote the software program, with out the annoying bugs of the earlier one, and built-in it into his house MQTT community powered by HomeAssistant. As a bonus, he additionally exhibits us the datalogger’s most important PCB, which turned out to be a peculiar creation – to not spoil the shock!

We think about this analysis isn’t simply helpful for if you face an analogous datalogger’s loss of life, however can be fairly helpful for individuals who discover themselves on the mercy of the pseudo-free cloud logging plan and wish to decide out. Photo voltaic tech appears to be an space the place Raspberry Pi boards and proprietary interfaces aren’t unusual, which is why we see hackers reverse-engineer photo voltaic power-related gadgets – as an example, try this exploration of a photo voltaic inverter’s proprietary protocol to get information out of it, or reverse-engineering an end-of-life decommissioned however completely wholesome photo voltaic inverter’s software program to get the service menu password.