I wrote my own code.
Not everything written in the scsi standard documentation is implemented by the book.
If you really want to access uncorrected data, the only semi-easy way I can think offhand for doing this would be adapting what programs like friidump do. This method doesn’t involve using any of the generic scsi read commands directly. (Friidump primarily uses the read buffer scsi command, which may be hardware/firmware/vendor specific in its behavior).
Read the friidump code and figure out whether the methods does what you want. (ie. Write your code using similar methods and examine the dumped data).