How to Erase the eMMC Storage

There are 4 different ways to erase all data on the onboard eMMC storage:

1. Keys Mode (Side-Buttons)
2. Serial Mode
3. Interrupt Mode
4. CLI Mode

Note: The operation of VIM1, VIM2 and VIM3 is almost the same, so this document will take VIM1 as an example.

Keys Mode(U-Boot is functional)

All ROMs we have released support eMMC erasure. Please follow the steps below to erase the data on the eMMC:

1. Power on VIM.
2. Long press Power and Function buttons simultaneously, without releasing them.
3. Short press the ‘Reset’ key and release.
4. After the operations above, the system will begin to erase automatically; it will take about 10 seconds to finish.
5. Your connected display/monitor will display a black screen when the erasure process is complete.

Serial Mode(For developers)

1. Refer to this guide (VIM1/VIM2/VIM3) to setup the Serial Tool for your VIM.
2. Once again, ensure you’ve done the correct connections and setup.
3. Hit any keys at the moment of bootup to stop autoboot. This step will make your VIM enter into u-boot mode.
4. Type store init 3 on the terminal of u-boot, and wait for the erasure process to complete.
5. Type reboot or press the Reset button
6. Use the following as a reference:

   kvim# 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

Tip:
If the erasure process completed successfully, the terminal should look like this 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;

Interrupt Mode

This approach is suitable for all products that use the Amlogic SoC:

1. Carry out normal upgrading via USB-C Cable(VIM1/VIM2/VIM3) or TF Card(VIM1/VIM2/VIM3).
2. Manually interrupt the upgrading process (forcefully disconnect after 15% is recommended). For example, unplug the USB-C cable or the TF card.
3. Power on your VIM again, and you’ll find that all the data on the eMMC has been erased.

CLI Mode

This approach is suitable for a VIM that has Linux installed:

1. Power on and boot up.
2. Open a terminal, and run dd to fill your bootloader partition with zeros:

   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