dd_bs=$((0x2f20))

dd if=/dev/urandom of=/tmp/wlan_data_0 bs=1M count=1
result=$(cat /tmp/wlan_data_0 | \
dd iflag=skip_bytes bs=$dd_bs skip=0 count=1 2>/dev/null | wc -c)
while [ ! $result -eq $dd_bs ]; do
echo "bad initial result"
result=$(cat /tmp/wlan_data_0 | \
dd iflag=skip_bytes bs=$dd_bs skip=0 count=1 2>/dev/null | wc -c)
done

counter=0
count_good=0
count_bad=0
echo "initial run $counter $result"

while true; do
counter=$(( counter + 1 ))
result_latest=$(cat /tmp/wlan_data_0 | \
dd iflag=skip_bytes bs=$((0x2f20)) skip=0 count=1 2>/dev/null | wc -c)
if [ "$result_latest" = "$result" ]; then
count_good=$(( count_good + 1 ))
#echo "run $counter okay"
else
count_bad=$(( count_bad + 1 ))
echo "run $counter bad $result_latest ($count_bad / $counter)"
#break
fi
done