Looks like heads per cylinder needs - 1

diff --git a/mkfs.c b/mkfs.c
index 311360754ff6fcad8cd47b111529f0368f163975..3fde2fe17ee2a646db1cdfb0189f897bf1fce797 100644 (file)
--- a/mkfs.c
+++ b/mkfs.c
@@ -1009,7 +1009,7 @@ static void write_reserved (void) {
     }
     
     write721_to_byte_array (bs.sectors_per_track, sectors_per_track);
-    write721_to_byte_array (bs.heads_per_cylinder, heads_per_cylinder);
+    write721_to_byte_array (bs.heads_per_cylinder, ((heads_per_cylinder >= 4) ? (heads_per_cylinder - 1) : heads_per_cylinder));
     write741_to_byte_array (bs.hidden_sectors, hidden_sectors);
     
     if (total_sectors > USHRT_MAX) {