Comment 2 for bug 1245578

Obviously, RAW scanning is completely disabled on purpose. In ledm.c I found the following in function set_scan_mode_side_effects:

   switch (scanMode)
   {
      case CE_K1: /* same as GRAY8 */
      case CE_GRAY8:
      case CE_COLOR8:
      default:
// ps->compressionList[j] = STR_COMPRESSION_NONE;
// ps->compressionMap[j++] = SF_RAW;
         ps->compressionList[j] = STR_COMPRESSION_JPEG;
         ps->compressionMap[j++] = SF_JPEG;
         ps->currentCompression = SF_JPEG;
         ps->option[LEDM_OPTION_JPEG_QUALITY].cap |= SANE_CAP_SOFT_SELECT; /* enable jpeg quality */
         break;
   }

Obviously, anything other than JPEG is disallowed. Enabling these two lines lets me select compression "none" without problems, but I still get the JPEG artifacts.