In attempting to backup and restore the firmware on my gen6.d board with avrdude and the USB connection to the printer, the board is now in a state where it no longer works and Pronterface cannot connect to it via USB. I am getting various sync errors whenever I try to upload anything to the board with avrdude or with the Arduino IDE.
I think the fundamental problem is that I have no programmer hardware, my gen6.d has no bootloader software installed, and my ham-fisted attempts to use avrdude over the USB connection (without separate programmer hardware) somehow messed up the device.
Before attempting to solve the problem in detail, I was wondering if it is even worth trying to solve. This gen6.d board was purchased 9 years ago and had Marlin 1.0.0 on it. I think I read that gen6 boards may not have enough RAM or ROM to run modern firmware like newer versions of Marlin. In particular I was hoping to try some firmware features like G29 manual bed leveling (https://marlinfw.org/docs/gcode/G029-mbl.html), but if this old gen6.d board doesn't have enough memory to run larger, more modern firmware, then I may just forget about trying to restore this old gen6.d board.
So, my questions:
1. Opinion-based question -- would you bother trying to recover a bricked gen6.d board, or is it too old to be useful these days, considering the RAM/ROM requirements of modern firmware?
2. Technical question -- given the basic situation that I bricked the gen6.d board with avrdude over the USB connection, is it still conceivable to be able recover the board back to a usable state if I buy and use an external programmer hardware device to reflash the gen6.d board?