Sadly, unlike my genuine Arduinos, all my clone Nano, Uno and Mega boards seem to have the same onboard refs, so there is no s/w way to identify them and treat them correctly and change the way the IDE handles them.
But the real problem is as Robin2 says in my other thread: Arduino developers seem to have very little interest in backwards compatibility.
I had this problem yesterday with my nanos... I solve it to downgrading to AVR Boards 1.6.20. A temporal solution... I guess.
genius, thank you very much
The problem as it occurs with uploading to Nano with Arduino AVR Boards 1.6.21 can be solved by simply selecting Tools > Board > ATmega328P (Old Bootloader). There's no need to uninstall or downgrade anything.The problem as it occurs for other boards will have a different cause and a different solution.
Selecting old bootloader would be simple if there was such an option. (I use the Linux version of the IDE.) Can you help me?