The on-board debugger is connected to the AVR128DB48 by default. These connections must be removed before any external microcontroller can be programmed or debugged. Cut the GPIO straps shown in the figure below with a sharp tool to disconnect the AVR128DB48 from the on-board debugger.
Figure 1. Programming and Debugging
Connections to Debugger
Info: Cutting
the connections to the debugger will disable programming, debugging, and data streaming
from the AVR128DB48 mounted on the board.
Tip: Solder in 0Ω resistors
across the footprints or short-circuit them with solder to reconnect the signals between
the on-board debugger and the AVR128DB48.