diff --git a/fragment.go b/fragment.go
index 674f2da65..ad9283551 100644
--- a/fragment.go
+++ b/fragment.go
@@ -2485,7 +2485,7 @@ func (f *fragment) importPositions(tx Tx, set, clear []uint64, rowSet map[uint64
 		err = doFunc()
 	}
 
-	if err != nil {
+	if err != nil && f.storage != nil {
 		// we got an error. it's possible that the error indicates that something went wrong.
 		mappedIn, mappedOut, unmappedIn, errs, e2 := f.storage.SanityCheckMapping(f.currdata.from, f.currdata.to)
 		if errs != 0 {
diff --git a/rbf/README.md b/rbf/README.md
index 4f6efa072..cbc5b74a7 100644
--- a/rbf/README.md
+++ b/rbf/README.md
@@ -93,12 +93,12 @@ The leaf page contains a series of cells with the header of:
 	[8] highbits
 	[4] flag
 	[4] child count
-	[*] array or RLE data
+	[*] array or RLE data or Handle (a pageno) to Bitmap Data
 
 
-### Bitmap page
+### Bitmap Data page
 
-The data for the bitmap page takes up the entire 8KB.
+The data for the bitmap data page takes up the entire 8KB.
 
 
 ## Proof of Concept Notes