Per Tillisch

[README.md](https://github.com/zevero/avr_boot#manual-installation) and the makefile both clearly document how to set the SD CS to any pin you like. If you want a much more simple solution just use the Arduino...

I understand now. The decision of whether to add that feature is up to zevero. It seems like a fairly rare use case since that's not a very common board...

I recently did a some shopping on Aliexpress for cheap SD cards to use with Arduino so I don't chance messing up my nice ones and I saw that you...

We haven't managed to get avr_boot working for uploading from SD to ATmega2560 yet (see https://github.com/zevero/avr_boot/issues/4) so if you can't get serial working for ATmega2560 that won't limit the functionality...

> I don't own a 1284p for testing, do you have any suggestions about what to get and where? I've gotten by for years a homemade ATmega1284P on a stripboard...

@zevero I'm the author of spi_pins.h so I can probably answer any questions about that file. As for stk500v1.c, not so much...

My understanding is that adding serial upload support for ATmega32U4 will still not allow uploading as you would normally to an ATmega32U4 based Arduino such as Leonardo, Pro Micro, etc....

I feel like a lot of the optimizations everyone is looking at doing here may have already been done in Optiboot. There may be more that can be done related...

I have been able to do serial and SD card upload to ATmega1284P and ATmega328P using your bootloader file. Good work! I must admit that even though you warned us...

I can also test ATmega32A and ATmega32U4. ATmega32A is not so commonly used in the Arduino world but there is already good support for it in MightyCore and it's a...