Hi Shu, I think I answered this in an earlier post, cut/pasted below:
Rather than making any hardware mods I decided to reconfigured u-boot to look for a specific key sequence before entering the u-boot console. To do this I firstly downloaded and rebuilt u-boot following instructions here: http://eewiki.net/display/linuxonarm/BeagleBone+Black# BeagleBoneBlack-Bootloader:U-Boot. (Testing with the default config produced the same 'failure' rate) I then modified '/include/config.h' in the u-boot source files, adding the following: #define CONFIG_AUTOBOOT_KEYED 1 #define CONFIG_AUTOBOOT_DELAY_STR "uboot" This now forces a user to enter the string 'uboot' before entering the u-boot console, otherwise the device will boot up normally. Rebuilding with this configuration still gave the same failure rate however. This is when I learned that the boot files on the eMMC flash are still loading before jumping to the files on the sd card I am using. So upon deleting the MLO file on the eMMC flash I had more luck. We setup a programmable power supply and a script looking at the output of uart0 to detect whether the device had successfully booted or had become stuck in u-boot, and then left it cycling power. We were then able to get many hundreds of consecutive successful boots - we only stopped the test because we decided it would probably never fail. So in the end it all came down to spurious data on uart0 - along with disabling booting from the eMMC. (we could have simply reconfigured u-boot on the eMMC in the same way, but disabling it drops a few seconds off the boot time). Thanks for all your help Gerald (and duckhunter). Regards, Andrew Glen On 4 November 2014 10:12, Shu Liu <[email protected]> wrote: > Mikkel, > > You don't have to remove the whole U15. You can just give a 3.3V pull-up > to the 4th PIN on the J1 connector. Then the board will not be stuck at the > UBOOT anymore. > > My question is how to fix it from software perspective? In u-Boot source, > how can we make sure it is not stuck? > > If anyone can answer my question, i would really appreciate it. > > Regards, > Shu > > On Friday, October 31, 2014 12:19:11 PM UTC-5, [email protected] wrote: >> >> >> On October 16th 2014 21.26.23 UTC+2 Gerald wrote: >>> >>> Is the power LED shutoff too? >>> Gerald >>> >> >> Hi Gerald. >> >> I'm also affected by the OP's issue of periodic failing boots on BBB (I >> got all REV Bs). >> >> My experience has always been with the power led lighting up and the >> system stuck without booting. Pressing the reset switch takes the system >> out of this locked up state, but neither boot switch or power switch has >> any effect. >> >> I am very interested in your input on the successful experiences put >> forward by Andrew and Marcus in May, about modifying uboot to remedy noise >> input on UART0_RXD (pin E15 of AM3358). >> >> I have done some tests today documenting the basic issue and some >> followup experiments investigating this specific cause, and I would >> appreciate if you could take a look and comment on the resulting >> speculations. You can find the details here; http://www.mikini.dk/index. >> php/2014/10/beaglebone-black-periodic-boot-failure- >> establishing-failure-rate-and-possible-cause. >> >> Executive summary; removing U15 (SN74LVC2G241: UART0 powerdown isolation) >> seems to remedy the boot issue on a CircuitCo-produced BBB in my possession. >> >> Although my result is inconclusive, as I was careless enough to rush >> myself into omitting a pre-modification test, verifying the failure rate of >> the unmodified BBB. >> >> >> Thanks in advance for your help, and for my Beagle puppies ;). >> Mikkel >> > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to a topic in the > Google Groups "BeagleBoard" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/beagleboard/aXv6An1xfqI/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
