I was baffled when Samsung decided to sunset the "Original SmartThings App" in order to move users over to the newer version. While I would normally be happy with such a decision, they switched everyone over without adding support for over half of the devices we have at home.
Switching to Home Assistant was always in the back of my mind, but I had never really gotten around to doing it partly because I would've needed to buy yet another Zigbee & Z-Wave hub.
Or so I thought
I opened up the Hub and started doing the usual, identifying the ICs and creating a basic block diagram. It didn't take long until I found the Zigbee chip, it was an Silicon Labs EM358x combo RF transciever and MCU.
Taking out the trusty ol' Dremel, I hacked off a whole corner of the board that contianed the Zigbee chip & pulled up the datasheet. I hooked up the MCU's UART pins to a old ESP8266 breakout board that I fried a while back (the USB to Serial converter was suprisingly still intact) and tried to see if Device Manager would detect anything.
What a surprise, it didn't work... Digging deeper into the datasheet, I found that you needed to supply a boot image on power up for some odd reason. I did however have access to an old copy of the Zigbee SDK that was floating around the internet, and I compiled a copy of it and tried to have it connect. It worked, so I flashed the basic EZSP protocol example and wrapped it in a bundle of Kapton tape.
Now, the Z-Wave part was a bit different. Samsung decided to go with a standard ZM5304 Z-Wave module for their Hub. Plugging it into a Serial to USB adapter showed no new devices on my computer until I rewrote the firmware using the Z-Wave utilities built into Simplicity Studio 5
Plugging both of these frankenboards into the old MacBook we have running Home Assistant resulted in two functioning radio interfaces that we now have in use 24/7 for around 2 months and have not encountered any issues.
Thanks for reading!