It's a fact that in the small world of super cheap electronics gadgets the STM8S003F3P6 has been largely superseded by the (more or less) electrically compatible Nuvoton N76E003AT20, an MCS51-style µC.
Chinese manufacturers are moving on. New designs appear, which are maybe easy to hack, maybe not. Replacing an TSSOP20 µC on a PCB isn't difficult, though, and I decided to give two new very cheap boards a try:
This one is available for $1.27 (incl. shipping); it clearly has a different circuit design than the ones explored so far in the HaD project. Since mo one west of China knows what's under the LED, I ordered one to figure that out. Maybe it's hackable.
Another one uses a more modern DC/DC converter silicon, the XL4015, but otherwise it looks very similar to the old design:
What's promising is the ISP pads on the backside of the board that show a pattern typical for boards with STM8 µC. I don't really expect one there, but who knows. I've seen it for $1.65 (incl. shipping), and maybe I can hack it to run STM8 eForth.