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I am working on IMX53 based customized board. When I boot the board there is no output after "Starting kernel ..." as shown below.

## Booting kernel from Legacy Image at 70800000 ...
   Image Name:   Linux-2.6.35.3
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    3009460 Bytes =  2.9 MB
   Load Address: 70008000
   Entry Point:  70008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK
OK

Starting kernel ...

I think this output is from U-boot, I am suspecting that there will be tty misconfiguration in the kernel. my doubt here is, the issue is with the console name which is there in U-boot enveronment settings or UART port number.

Can you help me to check console name and UART port used by U-boot(using U-boot 2009 on the board) to send log messages to minicom, so that I will check whether kernel is using the same console name and UART or not.

Thanks in advance.

user3693586
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    May be wrong console in kernel cmdline, but it also may be that kernel crashed on some early stage, before any output is actually printed to console. Try to enable earlyprintk in kernel to check this option. Also, if you want us to figure out your console device, please provide link to your u-boot repo and board name (i.e. which board name you are using to build u-boot). I believe that console name can be found from u-boot sources. – Sam Protsenko Oct 22 '15 at 08:11
  • First of all I highly recommend to update U-Boot to recent possible one. – 0andriy Oct 22 '15 at 08:40
  • Thanks for the reply. In Evk board latest U-boot(2015) was used, but not sure why client is using old u-boot(2008) on the target board. We are accessing the source through vpn. I could see the environment variables set using "CONFIG_EXTRA_ENV_SETTINGS" in board specific header file at include/configs/. I changed environment variables at u-boot prompt using set and saveenv, now when i change in "CONFIG_EXTRA_ENV_SETTINGS" it is not reflecting when i check with printenv at u-boot prompt. – user3693586 Oct 22 '15 at 11:06
  • I have flashed only kernel and u-boot on sdcard using "dd if=u-boot.bin of=/dev/sdc bs=512 seek=1 skip=1;dd if=uImage of=/dev/sdc bs=1M seek=1" commands. How space for env variables created between U-boot and kernel on sdcard. how I can clear the env variables saved between u-boot and kernel so that it will take env variables from u-boot. Can you help on this. – user3693586 Oct 22 '15 at 11:07
  • See http://stackoverflow.com/questions/18378563/how-do-i-find-arm-linux-entry-point-when-it-fails-to-uncompress/18392238#18392238 Freescale has zImage decompression code that requires the correct machine type, or else this pre-kernel code hangs. – sawdust Oct 22 '15 at 18:38
  • Thanks for the replies. I have flashed images in a new sdcard and then board is booting fine. I have dumped the new sdcard data to old sdcard using dd command then board is booting fine with old sdcard. I have doubht on env variables with the old sdcard, because I have changed variables using setenv and saved using saveenv at u-boot prompt. – user3693586 Nov 07 '15 at 16:15
  • I have doubhts about env variables, can you please help. When we flash images first on a sdcard then where u-boot will write env variables? If we change env variables using setenv and saveenv then during next boot U-boot will not change the env variables? – user3693586 Nov 07 '15 at 16:16
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    *"where u-boot will write env variables?"* -- That is configurable, but it is typically in the same manner that the U-Boot image is stored. E.G. if the U-Boot image is stored as an image on the the raw (without a filesystem) SD card, then the environment is probably also stored in a similar manner (i.e. in an unpartitioned area of the SD card for use by U-Boot). – sawdust Nov 11 '15 at 00:11
  • Thanks for the info. When I check U-boot source the env variables location on the flash is defined in board file using CONFIG_ENV_OFFSET and CONFIG_ENV_SIZE. How to flash the environment variables in to that location? If we won't flash anything into the env location on flash then U-boot will write the hardcoded environment variables(in boardfile) to env location on flash. – user3693586 Nov 12 '15 at 09:55
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    You may have to rebuild U-Boot with a new config that has **CONFIG_ENV_IS_IN_MMC**. Then use `dd if=/dev/zero of=XXX bs=512 count=NNN seek=SSS` to zero out the sectors on the SDcard. NNN should be CONFIG_ENV_SIZE / 512, and SSS = CONFIG_ENV_OFFSET / 512. **Be sure you use the MMC values and not the flash values.** On next startup U-Boot will detect an invalid saved environment, and resort to using a default environment (as defined by its configuration). Simply write the default (or an edited/modified version) environment using the **saveenv** command – sawdust Nov 14 '15 at 02:02

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