diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
index 155737e..a19480d 100644
--- a/drivers/mtd/devices/mtd_dataflash.c
+++ b/drivers/mtd/devices/mtd_dataflash.c
@@ -178,7 +178,7 @@
 		 * we're at a block boundary and need to erase the whole block.
 		 */
 		pageaddr = instr->addr / priv->page_size;
-		do_block = (pageaddr & 0x7) == 0 && instr->len <= blocksize;
+		do_block = (pageaddr & 0x7) == 0 && instr->len >= blocksize;
 		pageaddr = pageaddr << priv->page_offset;
 
 		command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;