You can override the pipeline's selection of calibration frame by using the ORAC-DR -calib command line option. Use this override judiciously, as in general the pipeline does a fine job.
The ORAC-DR -calib command line option is used by giving comma separated key=value pairs (e.g. '-calib dark=file1,bias=file2'). The following keys can be used for general instruments. Specific instruments may have extra calibration overrides that can be used.
baseshift - Use the given comma separated doublet (e.g. "0,0") as the frame's base position.
bias - Use the given frame as a bias.
dark - Use the given frame as a dark.
flat - Use the given frame as a flat.
mask - Use the given frame as a mask. This option is usually used for bad pixel masks.
polrefang - Add the given value to the measured polarisation angle to align the polarimeter's reference angle to north.
readnoise - Use the given value for the detector readnoise.
referenceoffset - Use the given comma separated doublet (e.g. "0,0") as the frame's reference offset, which is difference between the frame centre and the reference pixel derived from the FITS headers.
rotation - Use the given frame as a rotation matrix.
sky - Use the given frame as a sky observation.
standard - Use the given frame as a standard star observation.
When files are given the extension should be left off. As an example, if you have made a new bad pixel mask and wish to use it with ORAC-DR, the following command would be used:
oracdr -calib mask=new_bpm
ORAC-DR: Overview and General Introduction