Erase eMMC

There are 3 different ways to erase all data on the onboard eMMC storage:

  • Serial Mode (For developers)
  • Interrupt Mode
  • CLI Mode
The operation of VIM1, VIM2 and VIM3 is almost the same, so this document will take VIM1 as an example.
  • Refer to this guide to setup the Serial Tool for your VIM.
  • Once again, ensure you’ve done the correct connections and setup.
  • Hit any keys at the moment of bootup to stop autoboot. This step will make your VIM enter into u-boot mode.
  • Type store init 3 on the terminal of u-boot, and wait for the erasure process to complete.
  • Type reboot or press the Reset button
  • Use the following as a reference:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
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
kvim# reboot
Tips

If the erasure process completed successfully, the terminal should look like this when you power on your device:

1
GXL:BL1:9ac50e:a1974b;FEAT:ADFC318C;POC:3;RCY:0;EMMC:0;READ:0;CHK:AA;SD:800;USB:8;

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

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

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

  • Power on and boot up.
  • Open a terminal, and run dd to fill your bootloader partition with zeros:
1
2
3
4
5
6
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