fastboot flash sparse image: buffer aligned

Hi:

I'm testing 'fastboot flash' command with sparse images. Due to we write CHUNK_TYPE_RAW format data from unaligned buffer to mmc, the u-boot will report warinnig messages like this: "CACHE: Misaligned operation at range [84000028, 84001028]" if DCACHE is enabled. Is it a bug that we need fixed?

Thanks