--- a/doc/Low-level-commands	Wed Feb 17 19:54:57 2021 +0000
+++ b/doc/Low-level-commands	Wed Feb 17 20:41:30 2021 +0000
@@ -125,7 +125,15 @@
 to the SIM uses the PREVIOUS addressing mode, and there is no record number.
 This form is needed in order to write to cyclic EFs.
 
-restore-file
+restore-file File_ID host-bin-file
+
+This command restores a binary backup previously made with savebin back to the
+SIM, or writes new bits into the EF if you can construct the necessary binary
+image with tools like xxd.  The arguments are the same as for the savebin
+command.  This command supports all 3 types of EF (transparent, linear fixed
+and cyclic) and uses the correct UPDATE BINARY or UPDATE RECORD commands based
+on the SELECT response.  Cyclic files are restored by writing every record in
+the reverse order from the last index to the first.
 
 GSM authentication testing
 ==========================