BeagleBone Black n00b - maybe already corrupted eMMC?

[Nathan Wheeler]

Hey all,

I did a search - maybe someone is better at it than I am and could help connect me to an explanation/solution? Anyway, here's what has happened:

I got my board in the mail yesterday and connected it to my new MacBook Pro Retina (running OSX 10.11.3). I was able to ssh over USB after installing the included drivers and write/run code on the board. I didn't write anything special, just practiced loading a python example to the board.

I didn't know that pulling the USB cable without turning the board off via the Power button could corrupt the eMMC onboard. I understand I should have read the manual, but I think this information needs to be included on any "quick start" info provided to beginners. (If they tell you how to turn it on, shouldn't they tell you how to safely turn it off?) I have a lot of experience with Arduino and mistakenly thought that I could unplug the BeagleBone from power without any other shutdown steps.

So now, the board powers on and the user LEDs flash, and the board shows up as an external storage device on my laptop. But the IP address has changed to 198.168.7.1, and any attempts to ssh either result in a timeout or require password authentication. And the default passwords provided on Adafruit and other places are not working.

So, my questions are:
• How do I know if I've corrupted the data in the eMMC? Will the board act normally but not connect?
• If I can't ssh via USB, will I be able to do so via ethernet, or should I just start over/do a restore of Angstrom?
• Is Angstrom stiil the default distro, or are the boards shipping with Debian now?
• Is this possibly an El Capitan issue? I read a little about that, but I downloaded and installed a HoRNDIS version that was supposed to fix the issue.

Thanks for your help - I'm really looking forward to learning how to use this board and become part of the community. I build interactive interfaces for musical performance and am excited about the possibilities offered here.

- Nate

[Rick Mann]

I'd recommend connecting an appropriate USB-serial cable to the serial console header, and seeing what it spits out there during boot.

Alternatively, load a microSD card with a recent distro (I recommend Debian):

http://elinux.org/BeagleBoardDebian

Pop the SD card in and power on the board. It should boot from the SD card. If not, you need to hold a button down (not the power or reset buttons, the other one).

Note that images with "flasher" in the name will re-write the eMMC with that version. Console images are smaller and intended to be used via ssh or the serial console.

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[Nathan Wheeler]

Also, it's an Element 14 Rev C from Sparkfun.

[William Hermans]

So, question. If you removed the battery from your laptop, and then ran your laptop with no battery, an just yanked the power cord out of the wall to shut it down. What do you think would happen ? It's the same difference, except it would possibly take many more attempts at corrupting you laptop, before it did actually corrupt the file system.

Also, it's running Debian wheezy with a 3.8.x kernel, not Angstrom. Just so you know. RevC's all came with a *bone-47* 3.8 kernel.

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[Nathan Wheeler]

Thanks Rick, I'll try both of those things. I really appreciate your help.

-Nate

[Nathan Wheeler]

Hey William,

Yes, that's all very clear in hindsight. I do wish that I had looked up how to turn it off properly before I made the mistake.

Thank you for the clarification on the kernel. It's hard to find up-to-date info.

-Nate

[William Hermans]

Hey William,

Yes, that's all very clear in hindsight. I do wish that I had looked up how to turn it off properly before I made the mistake.

Thank you for the clarification on the kernel. It's hard to find up-to-date info.

-Nate

Ok, so now that we have that clear ;) hehe.

You have to treat this like you would any other computer. Except perhaps the beaglebone is more fragile. Due to hardware costs, and the fact that the software, that is specific to the beaglebone is written by various members of the community. Who by the way do not get paid to do that.

But you would shut down the BBB the same way you would shutdown your laptop from the command line.

$ sudo shutdown now -h

*or*

$ sudo halt

There is also a button closest to the ethernet jack which triggers an NMI through the PMIC, which should signal the processor to cleaning shut down linux. The button furthest from the ethernet jack on the same side ( left ) if I remember correctly is the reset button. So make sure not to press that while the OS is running either. The effect would be similar to pulling the power.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/7b283842-bf9c-4ef9-9793-c9639d13810f%40googlegroups.com.

[mickeyf]

The fact that the USB Gadget IP address shows up and that you can connect via ssh indicates that the OS is basically working. You may not have corrupted anything, but are simply not using the right password (which I don't remember either, but which I do remember was either non-intuitive or hard to track down....)

In the real world, BBBs and other devices will experience unexpected and unplanned power outages, should be designed, and up to a reasonable point are designed to survive them. I have both intentionally and unintentionally rudely removed power from BBBs many, many times (hundreds?) with no ill effects.

On the other hand, I do recall a certain 4 year old famously saying 'But I've run out in the street lots of times and never been hit by a car, Daddy!" You may want to avoid tempting fate unnecessarily.

In any case it is certainly quicker and easier to reflash a BBB than to, for example, rebuild an entire hard drive and reinstall a recent version of Windows on it.

[William Hermans]

In the real world, BBBs and other devices will experience unexpected and unplanned power outages, should be designed, and up to a reasonable point are designed to survive them. I have both intentionally and unintentionally rudely removed power from BBBs many, many times (hundreds?) with no ill effects.

I think you all expect far too much from an originally $45 SBC, and now a $55 SBC. All this stuff you all are talking about, including just changing an information card to tell people not to just yank power. Costs monies.

The cheapest solution right now to safe guard from  unexpected power outages. Is to buy a battery, and connect it to the PMIC test points. This will give the beaglebone enough time to issue a clean shutdown after input power goes missing. And that it exactly what it will do, power down.

Anyway, the above solution can be done for $10 or less, and if Gerald / circuitco designed this from the start, onto the beaglebone. It would at minimum have driven the price up $5 per board or more. For an option many people would not need or use.

So, if you need feature yourself. google "beaglebone UPS" and you'll find all kind of information. Then buy yourself a battery, and learn how to do this yourself . .

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/e0b0ef1e-56fa-456b-8d18-ca76ec3ae512%40googlegroups.com.

[William Hermans]

The cheapest solution right now to safe guard from  unexpected power outages. Is to buy a battery, and connect it to the PMIC test points. This will give the beaglebone enough time to issue a clean shutdown after input power goes missing. And that it exactly what it will do, power down.

Technically the cheapest option is free. Use USB power, plug into a laptop, and be sure to always issue shutdown now -h every time you need to power down.

[Nathan Wheeler]

Thanks for your response!