AnsweredAssumed Answered

When u-boot jump to serial downloader mode in u-boot?

Question asked by Mamoru Kanou on Aug 28, 2016
Latest reply on Aug 28, 2016 by igorpadykov

Hello commuity,


I have one question concern with low level boot sequence.


Environment :

 - i.MX6DL @800MHz

 - DDR3 x 4pcs. (64bit bus)

 - SPI-NOR (u-boot and kernel)

 - eMMC (RootFS)


When SPI-NOR boot is selected:

  i.e. BOOT_MODE[1:0]=Internal Boot, BOOT_CFG1[7:4]=Serial ROM(SPI)


In this case, the system boot up sequence is as following :

  1. ROM code copy 4K byte data (include IVT and DCD table) from
      SPI-NOR to OCRAM.
  2. Init the DDR base on the DCD table settings.
  3. Copy and Load the u-boot form SPI-NOR to DDR.
  4. Jump to DDR to executes the u-boot.


A piece of DDR  was broken after ESD test, so DDR stress test became fail.

In other word, maybe above process 3, 4 (i.e.Copy and Load the u-boot / jump to DDR address) is not executed.

In this case, the i.MX6 ROM BIOS will transition to the serial download mode?


Best Regards,