Flashing arduino board over rs485

I was wondering if it is already possible to flash an arduino board with a .hex over rs485. I found a topic over it which dates back to 2011
https://forum.arduino.cc/t/programming-over-rs-485/22651.

I know that the used stk 500 protocol is full duplex and requires the arduinos to send handshake signals back.

Is there a different/modified bootloader + upload protocol in existence with which you get to program an arduino board over rs-485?

Kind regards,

Bas

RS485 support was recently added to the Optiboot repository ( GitHub - Optiboot/optiboot: Small and Fast Bootloader for Arduino and other Atmel AVR chips )
You'd have to compile your own version, and I'm not entirely sure if it works very well. "rs485" is only about half of the issues involved. (But a couple of people have said it works for them.)