if (bus->seq < CONFIG_SANDBOX_SPI_MAX_BUS)
                        spec = state->spi[bus->seq][cs].spec;
                if (!spec) {
+                       debug("%s:  No spec found for bus %d, cs %d\n",
+                             __func__, bus->seq, cs);
                        ret = -ENOENT;
                        goto error;
                }
 
                file = strchr(spec, ':');
                if (!file) {
-                       printf("sandbox_sf: unable to parse file\n");
+                       printf("%s: unable to parse file\n", __func__);
                        ret = -EINVAL;
                        goto error;
                }
                        break;
        }
        if (!data->name) {
-               printf("sandbox_sf: unknown flash '%*s'\n", (int)idname_len,
+               printf("%s: unknown flash '%*s'\n", __func__, (int)idname_len,
                       spec);
                ret = -EINVAL;
                goto error;
        sbsf->fd = os_open(pdata->filename, 02);
        if (sbsf->fd == -1) {
                free(sbsf);
-               printf("sandbox_sf: unable to open file '%s'\n",
+               printf("%s: unable to open file '%s'\n", __func__,
                       pdata->filename);
                ret = -EIO;
                goto error;
         * yet. Perhaps we can figure something out.
         */
        state->spi[bus][cs].spec = spec;
+       debug("%s:  Setting up spec '%s' for bus %ld, cs %ld\n", __func__,
+             spec, bus, cs);
+
        return 0;
 }
 SANDBOX_CMDLINE_OPT(spi_sf, 1, "connect a SPI flash: <bus>:<cs>:<id>:<file>");
                                              __func__, busnum, cs);
                                        return ret;
                                }
+                               debug("%s:  Setting up spec '%s' for bus %d, cs %d\n",
+                                     __func__, spec, busnum, cs);
                        }
                }
        }