I'm designing copy of MKR WAN 1310 board but with reduced features and smaller board size. I'm using ATSAMD21G17D (128kB FLASH) instead of ATSAMD21G18A (256kB FLASH) in MKR 1310.
Can I use same libraries and settings as in MKR 1310? Or do I have to define somewhere that the processor has less memory?
I see that the "MattairTech Xeno Mini" board of the "MattairTech SAM D|L|C core for Arduino" boards platform has a Tools > Microcontroller > SAMD21G17A custom board option:
Not a perfect match for your part, but may work anyway (I didn't check what is the difference between them), or if nothing else maybe will be a good reference for making a custom board definition for your part.