EMMC flash storage wear level Wiren Board 5

eMMC Health Status

The following commands are used to get the estimated wear level of the eMMC flash storage chip used in Wiren Board 5 controllers:

Mount debugfs

mount -t debugfs none /sys/kernel/debug/

Read the wear level estimation

cat /sys/kernel/debug/mmc0/mmc0\:0001/ext_csd \
| python -c 'import binascii, sys; print "~%d%% wear" % (ord(binascii.unhexlify(sys.stdin.read().strip())[0x5e])*10)'

Example output:

~10% wear

The level is returned in multiplies of 10 percent. The minimum wear is 0% (new device), the maximum is supposed to be 100%.

Sources

• SanDisk SDIN7DP2-4G datasheet