r0b
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Wed May 09, 2012 5:45 pm

I'm having problems getting my Pi to boot consistently.

More often than not the red power LED comes on but it doesn't boot up.  Sometimes there's the tiniest flicker of the green LED when the power is switched on but it still doesn't boot.  Occasionally it will start first time, but generally I have to cycle the power a few times until it decides to play.

It does this even when there's nothing connected - i.e. just power lead and SD card plugged in.

When it does finally boot, it runs perfectly (I'm using the latest Debian squeeze image from the Downloads area).  However, if I issue a 'shutdown -r' only once has it every actually rebooted.  Every other time it's gone back to the state where it's sitting there with the red power LED and not doing anything.

Fortunately I've a friend with a functioning Pi (delivered the day after mine) and we've been able to do some back to back tests.

I suspected the SD card would be at fault but it turns out not to be the case.  My Pi exhibits the same problem with his SD card where as his Pi works perfectly with my SD card, keyboard, mouse, power supply, etc.

I'm planning on contacting Farnell tomorrow to return it but I was wondering if anyone has any suggestions before I do?

Steady_Bear
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Wed May 09, 2012 10:43 pm

Could still be the SD cards.

What brands are you using? It doesn't need to be a bad card for it not to work, it's just slightly 'off' spec, such that one Pi struggles to use it, but another is more comfortable.

Have you tried the very, very latest image of various distros? I know it's a hassle but some of the later stuff may have the updated kernel for improved SD drivers.

That said, if a different brand card working would still leave you worried about future use, then a replacement is probably the best route for you.

r0b
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Wed May 09, 2012 11:46 pm

I"m on the latest distro but it"s not actually getting as far starting to  load the OS.

Every card that"s been tried is on the compatible list except one. Two are actually the same make/model but bought 18 months apart.  The one that"s not on the list is a cheapo eBay card (circa 2006) that throws mmc0 errors occasionally once it starts but is just as stubborn to get going as the rest.

The other Pi will boot fine, first time every time off the same card with the same things attached.

Quite frankly, if it"s that sensitive to the SD card then something"s wrong with either the hardware or boot loader.

I"m going to send it back - it was a nice idea but not a good experience.

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jbeale
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 12:48 am

It certainly sounds like a hardware problem to me. There was another thread

http://www.raspberrypi.org/for.....work-again

about flaky booting behavior that was temperature-dependent.  Might be a marginal timing situation in the SoC or the SD card, might also be a component like a capacitor (the exact capacitance value is temperature-dependent) or a bad connection. If a power bypass cap has a cold solder joint so it is effectively out of the circuit, your digital signal could be noisy but still work- sometimes.

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mahjongg
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 12:59 am

sounds more like you simply are using an unreliable power source.

felixfurtak
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 3:45 am

I'm sure that you have tried many configurations, but one thing in your post stood out to me. You said:-

"My Pi exhibits the same problem with his SD card where as his Pi works perfectly with my SD card, keyboard, mouse, power supply, etc."

My question is have you tried your Pi with his SD card, keyboard, mouse and power supply?

Basically his system is working, so it would be wise to start with that and then swap only one component – his Pi for yours.

Also, keep the number of connected USB devices to a minimum since there are issues in current kernel with numerous USB devices and combinations thereof.

I suggest loose the mouse, and just have keyboard connected.

If you can get it to boot to the point of obtaining a dmesg dump then that would be useful.

Good luck!

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jbeale
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 5:18 am

"his Pi works perfectly with my SD card, keyboard, mouse, power supply, etc."

At some level that rules out everything but his Pi. You could argue that his power supply is right at the edge and his Pi is just slightly more sensitive to it, which I suppose is possible, but unlikely given "...when it does finally boot, it runs perfectly" because the Pi takes less power during initial boot, than when running applications. Anyway you could check for sure with a voltmeter as described at

http://elinux.org/R-Pi_Trouble.....r_problems

r0b
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 7:39 am

There's nothing of note in dmesg but then again it's not actually getting that far.

It doesn't seem to make any difference if powered-up with or without anything connected.  I don't think it's temperature dependent either, although that's difficult to quantify (it's only cold the first time it's booted and warm the rest of the time).

I've tried several power supplies - two genuine Apple chargers and a Garmin one, which I would hope are all good quality.  They're all rated at 5v 1A and the voltage across TP1/TP2 is within range on each.

If it can be persuaded to boot, it'll also run quite happily off a laptop USB port (with wireless keyboard/mouse, network and HDMI connected) so it seems unlikely to be a power issue.

WeaselNo7
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 4:23 pm

My current experience is that my Pi won't start from 'warm'...

If I leave it a while before a start up,  I'll get green flashing 'OK' light within a second or two of the 'PWR' light being lit.

If I restart it, either from the kernel, or from physical power disconnect/reconnect,  I only get the red 'PWR' light.

To me this suggests a temperature or a residual charge issue affecting the startup sequence (maybe this has knock on effects that cause a race condition with timings).

I've tried pretty much everything to get it to start from warm, including pressing down on the various components (especially BGA) at startup to counteract any warmth-induced warping,  but to no avail.

I've seen it suggested on another post that this could be explained by a slightly incompatible SD card, so I've gone ahead and ordered one of a brand that seems to be consistently good,  I'll let you know how it goes!

If that is the case, I'd still suggest it's a problem with the Pi, that makes it so temperamental with different SD cards.  Any thoughts from the hardware ninjas out there?

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carl_retrotext
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Re: Will not boot consistently - any suggestions before I send my Pi back?

Thu May 10, 2012 4:38 pm

WeaselNo7 said:


My current experience is that my Pi won't start from 'warm'...

If I leave it a while before a start up,  I'll get green flashing 'OK' light within a second or two of the 'PWR' light being lit.

If I restart it, either from the kernel, or from physical power disconnect/reconnect,  I only get the red 'PWR' light.

To me this suggests a temperature or a residual charge issue affecting the startup sequence (maybe this has knock on effects that cause a race condition with timings).

I've tried pretty much everything to get it to start from warm, including pressing down on the various components (especially BGA) at startup to counteract any warmth-induced warping,  but to no avail.

I've seen it suggested on another post that this could be explained by a slightly incompatible SD card, so I've gone ahead and ordered one of a brand that seems to be consistently good,  I'll let you know how it goes!

If that is the case, I'd still suggest it's a problem with the Pi, that makes it so temperamental with different SD cards.  Any thoughts from the hardware ninjas out there?


I found that mine wont boot from Cold, but is okay from warm, I have posted about this too.

I suspect as more people take delivery this will be an oft asked question.

There is a video in my thread about it, but I am happy as I now know how to get it running, if its power then It should NEVER work and if its the SD card then in time we will get proof.

WeaselNo7
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Re: Will not boot consistently - any suggestions before I se

Thu May 17, 2012 7:53 pm

Yup, I bought two MyMemory branded SD cards (from MyMemory.co.uk), and they work a real treat. I don't have any boot issues at all now. Apart from self-inflicted software-based ones, of course.

I recommend anyone with sporadic boot issues do the same.

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