[U-Boot] Environment "image" tool

[Mike Frysinger]

On Mon, Jul 18, 2011 at 15:52, Alessio Sangalli wrote:
> On 07/18/2011 10:59 AM, Mike Frysinger wrote:
>> although thinking about it a bit more, you probably could do it in shell.
>> (cat <env file> | tr '\n' '\0' ; dd if=/dev/zero count=1 ibs=1) > env.bin
>> env_size=8192
>> pad_size=$(( env_size - $(set -- $(du -b env.bin); echo $1) - 4))
>> dd if=/dev/zero ibs=$pad_size count=1 | tr '\0' '\377' >> env.bin
>>
>> and then you get the crc and prepend the 4 bytes
>> crc env.bin
>
> Hi! I am not sure here how you would calculate the crc in the shell
> script. Are you suggesting there is a command "crc(1)"?

there is indeed such a command.  the "xc" program suite provides one.
i'm sure there are others as well like `crc32`.

$ crc env.bin
5473921d    8188  env.bin
-mike