Howto Erase the eMMC Storage

There are many different ways to wipe out all the data on the onboard eMMC storage, and list as following:

  • Keys Mode
  • Serial Mode
  • Breaking Mode
  • CLI Mode

Keys Mode(U-Boot is running)

All the ROM we released support eMMC erasing, please follow the steps below to erase the data on eMMC:

  1. Power on VIMs.
  2. Long press Power and Function buttons simultaneously without release
  3. Short press ‘Reset’ key and release
  4. After the operations above, the system will begin to earse automately, and it will take around 10 seconds to done that.
  5. The display/monitor will display as a black screen when the wiping process is done.

Serial Mode(For developers)

  1. Refer this guidance to setup serial tool for VIMs.
  2. Make sure again you’ve done the right connections and setup.
  3. Hit any keys at the moment of booting to stop autoboot. This step will let VIMs boot into u-boot mode.
  4. Type store init 3 on the terminal of u-boot, and wait the wiping process to complete.
  5. Type reboot or press the Reset button
  6. References as following:
    Vim# store init 3
    emmc/sd response timeout, cmd8, status=0x1ff2800
    emmc/sd response timeout, cmd55, status=0x1ff2800
    [mmc_startup] mmc refix success
    [mmc_init] mmc init success
    switch to partitions #0, OK
    mmc1(part 0) is current device
    Device: SDIO Port C
    Manufacturer ID: 15
    OEM: 100
    Name: 8WPD3
    Tran Speed: 52000000
    Rd Block Len: 512
    MMC version 5.0
    High Capacity: Yes
    Capacity: 7.3 GiB
    mmc clock: 40000000
    Bus Width: 8-bit DDR
    [store]amlmmc erase 1emmckey_is_protected : protect
    start = 0,end = 57343


    Caution! Your devices Erase group is 0x400
    The erase range would be change to 0x36000~0xe8ffff

    start = 221184,end = 15269886
    Vim# reboot

Tips:
If the erase process complete, the printing should be like when you power on your device:

GXL:BL1:9ac50e:a1974b;FEAT:ADFC318C;POC:3;RCY:0;EMMC:0;READ:0;CHK:AA;SD:800;USB:8;

Breaking Mode

This approach suits for all Amlogic SoCs based products:

  1. Do normal upgrading via USB-C cable mode or TF card burning card mode.
  2. Break out during the upgrade process(break after 15% process is recommended), for example, plug-out the USB-C cable or the TF card.
  3. Power on VIMs again, and you’ll find all the data on eMMC have been wiped out.

CLI Mode

This approach suits for a Linux Distro preinstalled device:

  1. Power on and boot up.
  2. Open a terminal, run dd to fulfilled bootloader partition with zero:
    root@Khadas:~# dd if=/dev/zero of=/dev/bootloader
    dd: writing to '/dev/bootloader': No space left on device
    8193+0 records in
    8192+0 records out
    4194304 bytes (4.2 MB, 4.0 MiB) copied, 1.1226 s, 3.7 MB/s
    root@Khadas:~# reboot