Does optiboot use interrupts? My topic below where I had problems using the bootloader without a FTDI or other serial interface. It was solved by adding a small delay at the beginning of setup. Could it be an interrupt problem? So far the problem only seems to occur when Setup has a serial.begin at…

Optiboot

Topic		Replies	Views
Optiboot with FTDI breakout removed 3rd Party Boards	21	6658	May 6, 2021
Problems with Optiboot vs. Standard Arduino Bootloader on Custom Board 3rd Party Boards	7	3507	May 6, 2021
Optiboot + watchdog 3rd Party Boards	4	2788	May 6, 2021
Uno Bootloader Fixer... Troubleshooting	11	53768	May 6, 2021
Optiboot on 8MHz Arduinos General Guidance	12	4740	May 5, 2021