Kiwi fails to show after power cut

After a power outage at my remote location, the Kiwi is not longer visible. We discussed this in private before I believe, and the solution was to remove and reinstall the power plug with the ethernet cable attached. However, when the Kiwi is situated remote, this is not an option. Soooo.... The Kiwi really should be able to power on  and be visible after a power outage. I am 100 % sure the Kiwi has power, as it shares a PSU with two Perseus SDRs which are operational.


  • In general there should not be a problem with reboots after a power failure assuming the eMMC flash was not in the middle of a critical write operation that has left a damaged filesystem. Early BeagleBone Blacks (rev A6 and earlier) has a problem where the power-on reset signal wasn't long enough to ensure a reliable reboot. But even the Beta test Kiwis were all shipped with rev B Beagles so this should only be a potential issue for people who have supplied their own early revision Beagles.

    Not to say that this can't be happening, but I don't believe it is a generally observed problem. I just pulled the power on my BBG running v1.30 and it booted up fine after a reconnection. Now there might be an issue with short-term power "glitches" due to mains under voltage, lightning, etc. It may be possible to put the Beagle's power management IC (PMIC) into a weird state this way. Ideally one should use a little UPS so there is some hold-over or at least better power down/up sequencing for situations where the Beagle is located far away. And of course having the Kiwi's power supervised by a network-controlled switch would be ideal.
  • The difference between your test and what happened at my place was that both the Kiwi and the router powered off, and the Kiwi most likely powered on before the router. I believe we discussed this a while ago, though I can't find the email exchange - that the ethernet connection needs to be up before powering up. Or did I misunderstand?
  • Sorry, Ethernet problems. Yes, I remember now.

    The story with Ethernet PHY problems on the BBB/BBG is a little bit different. I just tried it here a few times to refresh my memory. It used to be the case that Ethernet always had to be connected to a powered-on switch before Beagle power-on or the Ethernet PHY would not initialize properly. And if you ever pulled the Ethernet cable while the Beagle was running, and then reconnected, the PHY would never get reset and the green & yellow lights on the RJ45 would never come back on.

    After years of this situation they finally fixed the PHY code to reset on a cable replug and you now always get the green & yellow lights. But what seems to still be a problem is when booting: If the Ethernet is disconnected when you boot, then when you later connect the cable you'll get lights but it seems DHCP (or something similar) has a 50% chance of working and allowing the Ethernet to work from that point. I haven't tried it with a static IP configuration (did you ever convert yours to a static IP?) I tried rebooting here on both BBB and BBG-based Kiwis a few times with the Ethernet unplugged and got about 50% successful connects. Simple disconnecting and replugging while the Beagle was already booted always seemed to work.

    So yes, there is going to be a problem if your switch and/or router is powering on significantly after the Kiwi such that the Kiwi DHCP (or whatever the real problem is) doesn't get a response at the right point in the boot process. There isn't much I can do about this unfortunately.

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