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We have several different ways to erase bootloader.
SPACE
on the keyboard to enter the U-Boot mode.store boot_erase bootloader
into the U-Boot console, and wait for the erasure process to complete.reboot
or press the RESET
button on your SBC.Use the following serial Terminal print-out as a reference:
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 8191 blocks erased: OK Caution! Your devices Erase group is 0x400 The erase range would be change to 0x0~0x23ff 8191 blocks erased: OK Caution! Your devices Erase group is 0x400 The erase range would be change to 0x0~0x23ff 8191 blocks erased: OK kvim1s# reboot
If the eMMC has been erased, the serial Terminal should show this print-out when your SBC powers-on:
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;
This erasure method is suitable for all products that use the Amlogic SoC:
eMMC boot-loader can be stored on /dev/mmcblk0
and special areas /dev/mmcblk0boot0
or /dev/mmcblk0boot0
.
dd if=/dev/zero count=1 bs=1M | sudo tee /dev/mmcblk?boot? >/dev/null
ls -1 /dev/mmcblk?boot? /dev/bootloader?
/dev/bootloader?
is just aliases for /dev/mmcblk?boot?
This example display empty content for special boot-loaders areas.
~$ for m in /dev/mmcblk?boot?;do dd if=$m count=1 2>/dev/null | hexdump -C; done
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000200
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000200
Next example display valid boot-loader header @ML
.
~$ dd if=/dev/mmcblk2 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.........|