I am developing a system to download Sentinel2 images, correct them with sen2cor, and obtain the NDVI for certain areas. As whole products are rather large, I was hoping that it would be possible to omit the bands which are not needed for NDVI calculation (only B04 and B08 are required for this task as far as I know). If I understood this post correctly, I will also need B02 and B03 in order for sen2cor to work.
I am able to download only the selected bands by specifying them in the download url from scihub (although one by one, which is not the most convenient way), i.e.:
But I am unsure about how to process this four (one per band) .jp2 images with sen2cor. Is it possible, to begin with, or do I need more files (thinking of the .xml file inside the .SAFE)? If so, is there an easy (only option I can think of is downloading all the files one by one) way to download this subset of data?