IMP005 "bricking" During FactoryBlinkup\IMPOS Upgrade

Hi,

On more than one occasion we have seen an IMP005 breakout dev board(imp005 Breakout | Dev Center) get temporarily bricked when powering off the module while it is performing a factory blinkup and/or while performing an impOS upgrade. The only way we then are able to recover the device is by re-cloudifying the IMP. This has happened at least twice in testing, but has not been reproduced since. I will be attempting to reproduce this in the following days as we may be frequently power cycling during the factoryBlinkup on our test fixture.

Steps:

  1. Power up IMP005 device (running fixture code)
  2. Start DUT factoryBlinkup (from IMP005 to DUT)
  3. While blinkup is in action, power-off IMP005 fixture device
  4. Power up IMP005 device - when “bricked” the IMP will power on and only display a solid green color on the status LED. It will not show as “online” in IMPcentral, and will not run any of the squirrel code.
  5. It can now only be recovered by re-cloudifying the module.

I will update more if this is reproduced in the coming days.

Thanks,
Jared

That’s very strange, as nothing is even written to flash during this process (let alone the OS area).

How old is your breakout? Early imp005 breakouts (maybe… pre rev3 or 4?) didn’t have a reset supervisor chip, which meant that short power cycles - ie brownouts - could leave the chip in an indeterminate state which would look like this. If you still saw it not booting after powered down for tens of seconds though, this is unlikely to be the issue. Broadcom (now cypress) issued an errata about this and we fitted reset supervisors to later revisions.

It’s possible that the fixture you built is keeping the supply up a bit during the power cycle (eg if you’re cycling AC power, there may be enough downstream capacitance to end up just browning out the device vs a full POR).

If you can reproduce it, and a long power cycle does not recover it, please either image the flash chip and send us the image, or send the board so we can extract the image from the flash.