[avrdude-dev] Bug in AVR8X XPlained Mini FW preventing Avrdude connection

[JanEgil.Ruud]

Hi all,

During recent work we have discovered a bug in the mEDBG FW, used on AVR8X 
XPlained Mini kits (with UPDI), that is preventing Avrdude from connecting. The 
error is fixed in mEDBG UPDI FW version 1.12 (and later).

The error message you get is "avrdude: jtag3_edbg_recv(): Inconsistent fragment 
number; expect 1, got 0", but what is causing the issue is the CMSIS-DAP 
commands sent in jtag3_edbg_prepare() and jtag3_edbg_signoff(). These command 
are superfluous on mini kits and could be skipped by adding a test if 
programmer id ends with "mini_updi".

But, there are not a lot of AVR8X XPlained Mini kits in circulation, and even 
fewer Avrdude users with AVR8X XPlained Mini kits. I'm a bit reluctant to 
implement the workaround in Avrdude since Avrdude really does nothing wrong, 
and everybody with a AVR8X XPlained Mini kits also has Atmel Studio which will 
upgrade the FW once it's out (since Avrdude hasn't had support for AVR8X 
XPlained Mini kits until now).

Any views on this? If not I'll leave it at this. At least you are aware of it 
now.

-Jan Egil