diff --git a/contrib/mapcache_detail/mapcache_detail.c b/contrib/mapcache_detail/mapcache_detail.c
index 9a33baad..371fe130 100644
--- a/contrib/mapcache_detail/mapcache_detail.c
+++ b/contrib/mapcache_detail/mapcache_detail.c
@@ -1269,6 +1269,7 @@ int main(int argc, char * argv[])
     mapcache_extent_i db_region_bbox;
     int dbx_has_inv = FALSE;
     int dby_has_inv = FALSE;
+    int file_zoom_level;
 
     // Select cache according to zoom level
     for ( cid=0 ; cid < caches->nelts ; cid++ ) {
@@ -1292,10 +1293,22 @@ int main(int argc, char * argv[])
 
     // Compute region bounding box expressed in tiles and in DB files for the
     // current zoom level
-    mapcache_grid_get_xy(&ctx, grid, region_bbox.minx, region_bbox.miny, iz,
-        &(til_region_bbox.minx), &(til_region_bbox.miny));
-    mapcache_grid_get_xy(&ctx, grid, region_bbox.maxx, region_bbox.maxy, iz,
-        &(til_region_bbox.maxx), &(til_region_bbox.maxy));
+    file_zoom_level = iz;
+    if (cache->top > 0) file_zoom_level = cache->top;
+    mapcache_grid_get_xy(&ctx, grid, region_bbox.minx, region_bbox.miny,
+        file_zoom_level, &(til_region_bbox.minx), &(til_region_bbox.miny));
+    mapcache_grid_get_xy(&ctx, grid, region_bbox.maxx, region_bbox.maxy,
+        file_zoom_level, &(til_region_bbox.maxx), &(til_region_bbox.maxy));
+    if (til_region_bbox.minx > til_region_bbox.maxx) {
+      int swap = til_region_bbox.maxx;
+      til_region_bbox.maxx = til_region_bbox.minx;
+      til_region_bbox.minx = swap;
+    }
+    if (til_region_bbox.miny > til_region_bbox.maxy) {
+      int swap = til_region_bbox.maxy;
+      til_region_bbox.maxy = til_region_bbox.miny;
+      til_region_bbox.miny = swap;
+    }
 
     dbx_has_inv = strstr(cache->dbfile,"{inv_x}")
       || strstr(cache->dbfile,"{inv_div_x}")
@@ -1304,10 +1317,6 @@ int main(int argc, char * argv[])
       || strstr(cache->dbfile,"{inv_div_y}")
       || strstr(cache->dbfile,"{inv_top_y}");
     if (cache->top > 0) {
-      mapcache_grid_get_xy(&ctx, grid, region_bbox.minx, region_bbox.miny,
-          cache->top, &(til_region_bbox.minx), &(til_region_bbox.miny));
-      mapcache_grid_get_xy(&ctx, grid, region_bbox.maxx, region_bbox.maxy,
-          cache->top, &(til_region_bbox.maxx), &(til_region_bbox.maxy));
       if (dbx_has_inv) {
         db_region_bbox.minx = grid->levels[cache->top]->maxx-1 - til_region_bbox.maxx;
         db_region_bbox.maxx = grid->levels[cache->top]->maxx-1 - til_region_bbox.minx;
@@ -1360,7 +1369,6 @@ int main(int argc, char * argv[])
         apr_finfo_t fileinfo;
         mapcache_extent_i til_file_bbox;
         mapcache_extent file_bbox;
-        int file_zoom_level;
         mapcache_extent temp_bbox;
         mapcache_extent region_in_file_bbox;
 #ifdef USE_CLIPPERS
@@ -1434,23 +1442,21 @@ int main(int argc, char * argv[])
 
         // Compute file bounding box expressed in tiles
         if (cache->top > 0) {
-          file_zoom_level = cache->top;
           if (dbx_has_inv) {
-            til_file_bbox.minx = grid->levels[file_zoom_level]->maxx-1 - ix;
+            til_file_bbox.minx = grid->levels[cache->top]->maxx-1 - ix;
             til_file_bbox.maxx = til_file_bbox.minx;
           } else {
             til_file_bbox.minx = ix;
             til_file_bbox.maxx = til_file_bbox.minx;
           }
           if (dby_has_inv) {
-            til_file_bbox.miny = grid->levels[file_zoom_level]->maxy-1 - iy;
+            til_file_bbox.miny = grid->levels[cache->top]->maxy-1 - iy;
             til_file_bbox.maxy = til_file_bbox.miny;
           } else {
             til_file_bbox.miny = iy;
             til_file_bbox.maxy = til_file_bbox.miny;
           }
         } else if ((cache->xcount > 0) && (cache->ycount > 0)) {
-          file_zoom_level = iz;
           if (dbx_has_inv) {
             til_file_bbox.maxx = grid->levels[iz]->maxx-1 - ix * cache->xcount;
             til_file_bbox.minx = til_file_bbox.maxx + cache->xcount + 1;
@@ -1474,7 +1480,6 @@ int main(int argc, char * argv[])
             til_file_bbox.maxy = grid->levels[iz]->maxy - 1;
           }
         } else {
-          file_zoom_level = iz;
           til_file_bbox.minx = 0;
           til_file_bbox.miny = 0;
           til_file_bbox.maxx = grid->levels[iz]->maxx - 1;
@@ -1493,6 +1498,16 @@ int main(int argc, char * argv[])
         if (GC_HAS_ERROR(&ctx)) goto failure;
         file_bbox.maxx = temp_bbox.maxx;
         file_bbox.maxy = temp_bbox.maxy;
+        if (file_bbox.minx > file_bbox.maxx) {
+          int swap = file_bbox.maxx;
+          file_bbox.maxx = file_bbox.minx;
+          file_bbox.minx = swap;
+        }
+        if (file_bbox.miny > file_bbox.maxy) {
+          int swap = file_bbox.maxy;
+          file_bbox.maxy = file_bbox.miny;
+          file_bbox.miny = swap;
+        }
 
         // Compute part of region of interest within file bounding box
 #ifdef USE_CLIPPERS
@@ -1559,6 +1574,16 @@ int main(int argc, char * argv[])
         mapcache_grid_get_xy(&ctx, grid, region_in_file_bbox.maxx-res,
             region_in_file_bbox.maxy-res, iz, &(til_region_in_file_bbox.maxx),
             &(til_region_in_file_bbox.maxy));
+        if (til_region_in_file_bbox.minx > til_region_in_file_bbox.maxx) {
+          int swap = til_region_in_file_bbox.maxx;
+          til_region_in_file_bbox.maxx = til_region_in_file_bbox.minx;
+          til_region_in_file_bbox.minx = swap;
+        }
+        if (til_region_in_file_bbox.miny > til_region_in_file_bbox.maxy) {
+          int swap = til_region_in_file_bbox.maxy;
+          til_region_in_file_bbox.maxy = til_region_in_file_bbox.miny;
+          til_region_in_file_bbox.miny = swap;
+        }
         if ((cache->xcount > 0) && (cache->ycount > 0)) {
           if (til_region_in_file_bbox.maxx>(til_file_bbox.minx+cache->xcount-1))
           {