On 6/4/19 4:05 AM, Gene Cumm via Syslinux wrote:> On Sat, May 25, 2019 at 8:33 AM Johann Obermayr via Syslinux
> <syslinux at syslinux.org> wrote:
>>
>> Hello,
>>
>> Is there a function to check a bzImage CRC ?
>>
>> If (ImageCRC("/bzImage") == -1)
>> Load_kernel("/BACKUP/bzImage") or what else
>>
>> Thanks
>>
>> Regards
>> Johann
>
> It doesn't appear so. I'm assuming you're referring to the
CRC32
> present in Linux x86 boot protocol 2.08+ found in Linux versions
> 2.6.26+ ? libupload has a CRC-16 function. zlib has a CRC-32
> function but looks like it's initialized with different
> polynomial/remainder.
>
Writing a generic CRC generator is not very hard; for a boot loader it makes
sense to compute the tables at runtime anyway, so it isn't a hard thing to
do.
However, the CRC polynomial for zlib and the Linux kernel should both be the
same: 0x04c11db7.
-hpa