MAC address is wrong

I have an imp with a printed mac of 0c2a69001245. It blinks-up okay (green flash at end).

When I power it up, I get 3 green flashes, then a series of fast red flashes (ie, connects, then drops out).

It shows up in connected list on the router as Device-0011B7 with a mac address of 0c2a690011b7 (IP

Why is the mac address different? And I assume this is why it can’t maintain a connection?

I re-ran blinkup a few times and it now manages to connect reliably. It did a firmware update, but the mac address is still different. The address reported by the router does not agree with the address printed on the card (and the packaging it came in). The address reported by the router is the same as that returned by imp.getmacaddress().

In summary:

  • router and imp api says 0c2a690011b7
  • printing on card and packaging says 0c2a69001245

Oh dear, that’s not supposed to happen. The way our production currently works, it basically can’t happen, but I expect your imp came from an earlier production run, in which human error could possibly have caused MAC mix-ups.

However, the fact that it’s “wrong” won’t have any effect on the operation of your imp or its impees. It’ll just make things very confusing if we ever have to track something down by looking for it in our server logs!


Is this likely to be a single mistake, or is it likely that a whole bunch were incorrectly labeled? A swapped digit I could understand, but there’s a big difference between the two addresses. I realise the printing is irrelevant to the operation, but if there are others out there, it may cause some confusion.

I’ve scratched out the original printing, and written in the correct value on mine.

We did have an issue in early production where we relied upon an operator to scan a barcode attached to the device… this was too error-prone and after the first ~6000 units we switched to the imp self-tattooing method. It’s likely there were multiple MAC mismatches from the early production, but we’re only aware of a handful of them.

Nowadays, the imp is put into the laser fixture, which has an ATSHA just like any other impee. The imp powers up, IDs the fixture (like it would any other impee), loads the laser etch squirrel code, and then directs the fixture to etch its own address into its underside.

The rule is, when you think you’ve made something foolproof, the fools get more creative…

The rule is, when you think you've made something foolproof, the fools get more creative...
:-) I will remember that one