I've been busy with other things the last few days, and checking back on this forum, I saw the discussion led to an answer. I opened my S26 again, and indeed, a PUYA chip!!!!.
Next weekend, I'll resolder the wires, and flash it with the PUYA version.
Thanks everybody.

TD-er, thanks for your reply.

The problem I have is not with flashing the mega version of ESP easy. It flashes fine, but does not appear to be working. No AP is visible.

I tried to flash ESP_Easy_mega-20181017_normal_ESP8266_1024 on a Sonoff S26. I already did so sucesfully on a S20 earlier, and want to keep the firmare of the devices devices as much the same as possible. Although the flashing looked to go well, no Wifi AP appeared. I also tried ESP_Easy_mega-201810...