The Exynos series boot loader is placed on the Boot Partition(Hidden Partition) in the eMMC memory. (C1/C2 models don't use the Hidden partition).
When it is corrupted or you want to use the eMMC with other different board, you must install the proper boot loader in the eMMC.
Note that you must have a micro-SD card to run the recovery process.

Recoverying with Recovery image

  1. Download Recovery Image file.
  2. Prepare a microSD card and flash the downloaded image. flashing → refer this link
  3. Connect both the eMMC and MicroSD to XU3/XU4
  4. Set the dip-switches or slide-switch on XU3/XU4 to “SD boot mode”. If you have XU3, refer this link
  5. Connect Power and watch the LED status
  6. The blue and red LEDs are solid on. This may take 40seconds ~ 3minutes. After recovery process, blue LED will be flashing like a heartbeat. And remove the power supply.
  7. Set the dip-switchs or slide-switch back to eMMC boot mode.
  8. Remove the microSD card.
  9. Proceed with normal power up with your peripherals attached.
  10. After checking the Android on eMMC, you can install other Linux OS images on the eMMC later.

Recoverying eMMC with Micro SD card and USB-UART kit

This instruction requires USB-UART and terminal application on your desktop.

  1. Set the switch (SW1) to boot with MicroSD on the board
  2. Insert the Micro SD flashed with booting image into its slot and power on. You must stop at U-boot once the board is started.
  3. Invoke the commands below to copy the boot loader image from Micro SD to eMMC. Once copying is done, set the switch (SW) to see if the board can boot with eMMC.
Exynos5422 # run copy_uboot_sd2emmc