$ md5sum spi.bin
8b2b9cd89007e81ece9144f0f10fb0da spi.bin
$ md5sum spi.bin >> hash.md5
$ md5sum uImage >>hash.md5
$ md5sum userdata.img >> hash.md5
$ cat hash.md5
8b2b9cd89007e81ece9144f0f10fb0da spi.bin
010b406c78600750d5b2fee1f41cd9c7 uImage
bf087ed03d197829a1966b0debd51f01 userdata.img