Am 22.09.2017 um 08:28 schrieb Chris Johns: > On 22/09/2017 16:13, Sichen Zhao wrote: >> Can you please tell me which version of u-boot you used? >> My version is old: U-Boot SPL 2014.04-00014-g47880f5 (Apr 22 2014 - >> 13:23:54) > > I built git://git.denx.de/u-boot.git master and I think commit > 8a1c44271c55961fb70fb6177f9c02fdb05287c5. Looking at the trace in a little > more > detail I see `U-Boot 2013.04-dirty (Jul 10 2013 - 14:02:53)` which seems > wrong. > I am now confused. > > My uEnv.txt is being read from the mmc ... > > ] gpio: pin 53 (gpio 53) value is 1 > ] mmc0 is current device > ] micro SD card found > ] mmc0 is current device > ] gpio: pin 54 (gpio 54) value is 1 > ] SD/MMC found on device 0 > ] reading uEnv.txt > ] 182 bytes read in 3 ms (58.6 KiB/s) > ] Loaded environment from uEnv.txt > > That is how I am controlling the boot. Could I be booting from the on-chip > flash? > > Chris
Hello Chris, first of all: I don't think that the problem depends on the U-Boot version. It sounds more like a problem due to the missing FDT. Maybe there is a check missing whether the register that should contain the FDT address is set correctly? Regarding the point which U-Boot is booted: The boot process on the Beagle Bone is a little odd. I'm still not 100% sure about it. Basically it seems roughly about the following: If you don't press the S2-Switch during power-up a first U-Boot ("U-Boot SPL") is read from the boot sector of the on-board eMMC. It loads a second U-Boot from the active partition of the eMMC. The second U-Boot checks a number of sources to boot from. I think that depends a little on the version of the U-Boot environment on the eMMC. My BBB (with a U-Boot 2014.04-00014-g47880f5) tries to read the uEnv.txt from the SD-Card and parses it if the file is available. If not it boots some default from the internal eMMC. If you press the S2-Switch during power-up (a reset isn't enough; it has to be a power cycle), the controller tries to boot from the SD-Card. If you have a "U-Boot SPL" in the boot sector there, it will use this U-Boot. I think I've read somewhere that it is possible to mark the internal partition as "not active" so that the U-Boot SPL of the eMMC directly starts the U-Boot from an active partition on the SD-Card instead. But I never tried or tested that. Regards Christian _______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel