yeayer

Here it is. [readtest_blink.txt](https://github.com/MCUdude/MegaCoreX/files/11087865/readtest_blink.txt)

For this one I used Arduino IDE with following settings: Board: "ATmega4809" Clock: "Internal 16MHz" BOD: "BOD 2.6V" EEPROM: "EEPROM retained" Pinout: "Nano Every" or I use "48pin", does not...

If I understand it correctly, the first lines are the bootloader and then the code appended starts on :2002000050C0000068C0000066C0000064C0000062C0000060C000005EC000005CC00000E0, which by the link you sent means address 0x200, right?

[test.ino.hex.txt](https://github.com/MCUdude/MegaCoreX/files/11088309/test.ino.hex.txt) [test.ino.with_bootloader.hex.txt](https://github.com/MCUdude/MegaCoreX/files/11088317/test.ino.with_bootloader.hex.txt) Should be these, one with and one without bootloader.

-patmega4809 -cjtag2updi -P/dev/ttyUSB2 -U fuses:r:-:h avrdude: AVR device initialized and ready to accept instructions avrdude: device signature = 0x1e9651 (probably m4809) avrdude: reading fuses memory ... avrdude: writing output file...

Now I did a test. I have tried to compile the code as for Arduino Every, took that one and manually created a .hex file with fuse setting for bootend...

Sorry for confusion, by the way, I really appreciate your support, thanks for the immediate replies! Here are the steps I have done to get to this point: 1: I...

Also, I found out that I can not read fuses through the serial3: avrdude -patmega4809 -carduino -P/dev/ttyUSB3 -U fuses:r:-:h avrdude: AVR device initialized and ready to accept instructions avrdude: device...

Unfortunately, when I choose pinout "Nano Every", it throws an error, I was always using "48 pin". `.arduino15/packages/MegaCoreX/hardware/megaavr/1.1.1/avrdude.conf -v -patmega4809 -carduino -P/dev/ttyUSB4 -e -Ufuses:w:0x00,0x54,0x01,0xff,0x00,0b11001001,0x06,0x00,0x02:m -Ulock:w:0xC5:m -Uflash:w:/tmp/arduino_build_518265/spiffs_test.ino.hex:i avrdude: Version 7.1-arduino.1 Copyright...

I have tried your solution, connected the programmer to UART1 alt pins and it works. So I think there must be something wrong with using UART3 ALT pins for programming...