The eMMC of burning writing system to Nanopc-t2 can't be solved successfully

According to the friendly official PC T2 wiki manual operation, make SD card to start, make nano PC T2 burn write system to eMMC;

copy of the friendly official related documents: as follows:

--------------------------------------------------------------A Part------------------------------------------------------------------------------------------
Burn Write system to nanopc-t2 emmc download Eflasher firmware

The firmware file name is: s5p4418-eflasher-sd8g-xxx-full.img.7z
This firmware contains a mini Ubuntu core system that can be launched with an SD card, as well as the latest version of the Debian, ANDROID5, Android4.4 and Ubuntu core system image files;
Download the s5p4418-eflasher-sd8g-xxx-full.img.7z to your computer, and also download the burn-in tool under Windows: Win32diskimager.rar;
Making SD boot card with Eflasher firmware

Unzip the firmware with 7z software, get. IMG End of the file, insert SDHC card under Windows (limit 4G and above cards), run Win32diskimager as Administrator, select Image file to load firmware, select your SD card letter, point Write That is, start writing image to SD card;
If your computer is using a Linux system, you can also use the DD command to extract the extracted. img files directly into the SD card to complete the production of the boot card;
Burn Write system to eMMC

Will make a good SD card into the nanopc-t2, connect HDMI or LCD, press and hold the screen next to a boot button, toggle the power switch, start the Development Board will see the system selection, choose you need to burn write to eMMC system.
-------------------------------------------------B Part--------------------------------------------------------------------------------
If the phenomenon occurs: After restarting, can enter the Uboot, but did not enter the new system;

The way I try to succeed is to fix it as follows:

1): Erase eMMC, Erase, uboot may be damaged,

2): Then the successful SDHC card in accordance with part A to insert T2 card slot, re-select the desired system burn write again, after completion, click Finish, and then restart the board, you can enter the new system:

Ways to erase eMMC:

Enter Uboot Terminal:
run 
1, select eMMC
u-boot# MMC dev 2 
mmc2 (part 0) are current device
2, Erase eMMC.
u-boot# MMC erase 0 20000
MMC Erase:dev # 1, Block # 0, Count 2097152