Suggestions on HP21 restoration

[blackjetrock]

I'm just having a bit of fun...

Fitting a display is sometimes a problem too. I have used these people quite a lot:

https://www.buydisplay.com/oled-display

They are fairly quick to supply and seem reliable. the displays are nice too.
Despite the low power claims I'd steer clear of epaper/eink displays as they take a long time to update.
On a low power theme, the RP2040 isn't particularly low power even with everything turned down. The STM32 is a bit better I think, but you do have to shut everything down.

Andrew