So, I suspect you’re running into the same problem as 000345 is only 150 imps later on than the 0002af you replaced 
Where did you get this replacement one from, and what are you plugging it into?
I have got first imp and two latter replacements from the Growerbot kickstarter project: Mr. Luke Iseman Link: http://www.growerbot.com/
I am plugging it into https://github.com/liseman/growerbot main board.
list of macs
0c2a690002af - first e-imp, green blinking, not working.
0c2a69000345 - replacement e-imp, green blinking, not working, currently connected.
0c3a690002f5 - not tested yet however doubt it will make any difference
So far I have tried 3 different routers, 2 mobile hotsports and 3 different ISP’s - makes absolutely no difference.
Any suggestions? Maybe there is a way to update the firmware version offline?
I suspect that there’s something strange going on with whatever code the growerbot had associated with it.
I’ve tweaked the ancient server that is used to deal with the first 1000 imps for their first boot (until they upgrade). Can you try all 3 again?
Hello Hugo,
Clearly something different is happening - all of them went trough
Downloading update
Installing Update
Orange-Green-red-Orange-Green-red combo for around a minute
Currently shows shows no blinking and still cannot see any in my IDE.
What do you see from your side?
Ah, this is progress. I see all 3 have upgraded and are running 27.10 now.
However, the device you have them plugged into appears to have a faulty ATSHA ID chip (or pull-up missing, or bad contact) and this is why it’s not appearing in the IDE, and may have been why they were stubborn in upgrading in the first place.
Thank you,
Is there any way I can test that (ATSHA)? I have tested the conenction and it is O.K
Pull up resistor is in place + gas a good contact.
Or just order another replacement as all the soldering of smd components have been done from the factory?
No easy way to test, no. If you have a scope you can look at the data pin. The imp will be trying to talk to it on power up, but you may not be able to determine the difference between outbound commands and inbound responses.
I’d personally just get an April board from digikey, sparkfun or adafruit and try the imps in there.