Slopie - "So I'm still looking for a suitable e-ink-color device"
I recently bought an Ectaco language learning tablet (colour lcd) and am puzzled that the company appears to be still in business. I am always dubious when reading GoodEreader articles and reviews but you might be interested to read the bit about Ectaco's disastrous ereader colour screen adventure.
https://goodereader.com/blog/electro...tten-e-readers
Apart from some suspect reviews saying it was the greatest thing since sliced bread customers were underwhelmed and the project flopped. Whether or not the Ectaco colour reader had a serial port or not I couldn't say. Probably not.