root@am62xx-evm:~# dd if=/dev/zero of=/dev/mmcblk0 bs=512 count=65536  
65536+0 records in
65536+0 records out
33554432 bytes (34 MB, 32 MiB) copied, 2.67735 s, 12.5 MB/s
root@am62xx-evm:~# dd if=/dev/zero of=/dev/mmcblk0 bs=512 count=2097152
2097152+0 records in
2097152+0 records out
1073741824 bytes (1,1 GB, 1.0 GiB) copied, 87.3268 s, 12.3 MB/s