Phytec L-1017e.A3 i.MX 8M Plus, Руководство пользователя

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L-1017e.A3 i.MX 8M Plus BSP Manual
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To ensure that the new setting has taken over, shut down the system:
target$ poweroff
and perform a power cycle. It is recommended that you verify the settings now.
First, check the value of ENH_SIZE_MULT which must be 3719168 KiB:
targe$ mmc extcsd read /dev/mmcblk2 | grep ENH_SIZE_MULT -A 1
You should receive:
Max Enhanced Area Size [MAX_ENH_SIZE_MULT]: 0x000764
i.e. 3719168 KiB
--
Enhanced User Data Area Size [ENH_SIZE_MULT]:
0x000764
i.e. 3719168 KiB
Finally, check the size of the device:
target$ parted -m /dev/mmcblk2 unit B print
BYT;
/dev/mmcblk2:31742492672B:sd/mmc:
512 : 512 :unknown:MMC S0J58X:;
Erasing the Device
It is possible to erase the eMMC device directly rather than overwriting it with zeros. The eMMC block management
algorithm will erase the underlying MLC memory cells or mark these blocks as discard . The data on the device is lost
and will be read back as zeros.
After booting from SD Card execute:
target$ blkdiscard -f --secure /dev/mmcblk2
The option --secure ensures that the command waits until the eMMC device has erased all blocks. The -f (force)
option disables all checking before erasing and it is needed when the eMMC device contains existing partitions with
data.
Tip
dd if=/dev/zero of=/dev/mmcblk2 also destroys all information on the device, but this command is bad for
wear leveling and takes much longer!
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