There are a bunch of posts online about how to add a custom bootscreen to a TS100 soldering iron. These things are great, if you get a little USB-C to jack adapter you can run them off a powerbank and they’re tiny so you can keep them with you wherever you go. Which of course you should.

I did have some trouble getting the image into the write format though, after messing around a little I settled on this command using ImageMagick:

convert image.png -depth 1 -monochrome BMP3:LOGOIN.BMP

Then you can use identify to check that the metadata of the output is indeed 1-bit in depth.

identify LOGOIN.BMP