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--- products:sbc:vim1s:development:erase-emmc [2022/07/17 21:51]
nick
+++ products:sbc:vim1s:development:erase-emmc [2022/08/24 02:00] (current)
hyphop old revision restored (2022/08/23 15:37)
@@ Line 1: / Line 1: @@
-====== VIM1S Erase eMMC ======
+====== VIM1S Erase eMMC bootloader ======
-There are 3 ways to erase the eMMC:
+We have several different ways to erase bootloader.
+=====U-Boot console======
-  * Serial Mode (Developers)
-  * Interrupt Mode
+  - Connect your PC to the SBC using a [[products:sbc:vim1s:development:setup-serial-tool|Serial Debug Tool]].
-  * CLI Mode
+  - As the SBC is booting-up, press ''SPACE''on the keyboard to enter the U-Boot mode.
+  - Type ''store boot_erase bootloader'' into the U-Boot console, and wait for the erasure process to complete.
+  - After erasure is completed, type ''reboot'' or press the ''RESET'' button on your SBC.
+Use the following serial Terminal print-out as a reference:
+```shell
+kvim1s# store boot_erase bootloader
+GUID Partition Table Header signature is wrong: 0x0 != 0x5452415020494645
+GUID Partition Table Header signature is wrong: 0x0 != 0x5452415020494645
+gpt is invalid
+Caution! Your devices Erase group is 0x400
+The erase range would be change to 0x0~0x23ff
+blocks erased: OK
+Caution! Your devices Erase group is 0x400
+The erase range would be change to 0x0~0x23ff
+blocks erased: OK
+Caution! Your devices Erase group is 0x400
+The erase range would be change to 0x0~0x23ff
+blocks erased: OK
+kvim1s# reboot
+```
+If the eMMC has been erased, the serial Terminal should show this print-out when your SBC powers-on:
+```txt
+S4:BL:25dcde;ID:00D9C31D04901F08;FEAT:30F:1FFF0000:B002F:1;POC:DD;RCY:0;OVD:0;DFU:0;USB:ADFU�S4:BL:25dcde;ID:00D9C31D04901F08;FEAT:30F:1FFF0000:B002F:1;POC:DD;RCY:0;OVD:0;DFU:1;USB:0;RD-00:0;
+```
+===== Interrupt Mode =====
+This erasure method is suitable for all products that use the Amlogic SoC:
+  - Carry out eMMC flashing via a [[products:sbc:vim1s:install-os:install-os-into-emmc-via-usb-tool|USB-C cable]].
+  - Manually interrupt the upgrading process (forcefully disconnect after 15% is recommended). For example, unplug the USB-C cable or eject the TF card.
+  - Power on your SBC again, and you'll find that all the data on the eMMC has been erased.
+===== Linux command-line =====
+eMMC boot-loader can be stored on ''/dev/mmcblk0'' and special areas ''/dev/mmcblk0boot0'' or ''/dev/mmcblk0boot0''.
+==== Cleanup eMMC boot loaders ====
+Cleanup special eMMC boot areas.
+```sh
+dd if=/dev/zero count=8192 | sudo tee /dev/mmcblk?boot? >/dev/null
+```
+Also need cleanup eMMC common boot area.
+```sh
+sudo dd if=/dev/zero count=2000 seek=1 of=/dev/mmcblk0
+```
+<WRAP important >
+''/dev/mmcblk0'' maybe different, please check how-to [[#get-block-device-names-for-boot-loaders]]
+</WRAP>
+==== Universal method for cleanup all eMMC boot-areas ====
+```sh
+sudo dd if=/dev/zero count=8192 | sudo tee /dev/mmcblk?boot? >/dev/null
+sudo dd if=/dev/zero count=2000 seek=1 of=$(ls /dev/mmcblk?boot?|grep -m1 -o /dev/mmcblk.)
+```
+==== Get block-device names for boot loaders ====
+Get block-device names for special boot areas.
+```shell
+~$ ls -1 /dev/mmcblk?boot? /dev/bootloader?
+/dev/bootloader0
+/dev/bootloader1
+/dev/mmcblk0boot0
+/dev/mmcblk0boot1
+```
+<WRAP important >
+''/dev/bootloader?'' same areas as ''/dev/mmcblk?boot?'', but shifted by 512 bytes
+</WRAP>
+Get eMMC block-device name.
+```shell
+~$ ls -1 $(ls /dev/mmcblk?boot?|grep -m1 -o /dev/mmcblk.)
+/dev/mmcblk0
+```
+==== How-to check boot loaders content ====
+This example display empty content for special boot-loaders areas.
+```shell
+~$ for m in /dev/bootloader?;do echo $m; dd if=$m count=1 2>/dev/null | hexdump -C ;done
+/dev/bootloader0
+00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00000200
+/dev/bootloader1
+00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00000200
+```
+Display same but for other boot areas names.
+```shell
+~$ for m in /dev/mmcblk?boot?;do echo $m; dd if=$m skip=1 count=1 2>/dev/null | hexdump -C ;done
+/dev/mmcblk2boot0
+00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00000200
+/dev/mmcblk2boot1
+00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
+*
+00000200
+```
+Next example display valid boot loader header ''@ML''.
+```shell
+~$ dd if=/dev/mmcblk0 count=1 skip=1 2>/dev/null | hexdump -C | head -n1
+00000000  40 4d 4c 20 8d 66 31 ed  00 00 00 00 80 05 00 00  |@ML .f1.........|
+```
+/*
+This erasure method is suitable for the SBC with Linux installed:
+  - Power on and boot up.
+  - Open a Terminal, and run ''dd'' to fill your bootloader partition with zeros:
+```shell
+khadas@Khadas:~$ sudo dd if=/dev/zero of=/dev/bootloader
+dd: writing to '/dev/bootloader': No space left on device
++0 records in
++0 records out
+4194304 bytes (4.2 MB, 4.0 MiB) copied, 1.1226 s, 3.7 MB/s
+root@Khadas:~# reboot
+```
+*/

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