PROCEDURE TO FLASH eMMC

[Im4Tinker]

I've done this way, which is pretty quick.
The only problem is about the partition table which won't be consistent. So it might be better to install only the u-boot image. In such way the previous setup still available to use, and saving time to update the packages that where already done.
First step:

• Have the previous installation copied onto as SD card, whichever is preferred
  
• Boot from SD, following the indication to set the jumper to MASKROM
  
• Locate the kernel name of the disk
  Code:

  $ sudo fdisk -l
  For example we assume /dev/mmcblk0 for eMMC and /dev/mmcblk1 for SD card
  
• Copy the u-boot from SD card to eMMC
  Code:

  $ sudo dd if=/dev/mmcblk1 of=/dev/mmcblk0 bs=512 seek=64 count=4032 conv=noerror,notrunc

This way will need to write less than 2 Mb, which suffices for most of the cases. Usually the u-boot is not bigger than 460 Kb. Also it prevent to upset the previous partition and they'll come back to be used again. The only advise is to use the same previous installation, whatever is TinkerOS, or Armbian or Volumio or else.
For convenience it might be good to save that portion into SD card, so if it will happen again, is less troubles to resume. Therefore the command become inverted for saving

Code:

$ sudo dd if=/dev/mmcblk0 of=BackupFile.img bs=512 seek=64 count=4032 conv=noerror,notrunc

Then next time BackupFile.img will be used