Convert the GeoTIFF file to a compatible format (e.g. LAN). This can be done in one of two ways. From a system shell, use gdal_translate:
gdal_translate -of LAN file.tif file.lan
Or similar within Python:
from osgeo import gdal
src_fname = 'file.tif'
dst_fname = 'file.lan'
driver = gdal.GetDriverByName('LAN')
sds = gdal.Open(src_fname)
dst = driver.CreateCopy(dst_fname, sds)
dst = None # close dataset; the file can now be used by other processes
Note that the first method is actually better, as it also transfers other metadata, such as the spatial reference system and possibly other data. To correctly do the same in Python would require adding more lines of code.