diff --git a/cmd/sf.c b/cmd/sf.c
index 8713736..cd50b38 100644
--- a/cmd/sf.c
+++ b/cmd/sf.c
@@ -294,6 +294,12 @@
 		return 1;
 	}
 
+	if (strncmp(argv[0], "read", 4) != 0 && flash->flash_is_unlocked &&
+	    !flash->flash_is_unlocked(flash, offset, len)) {
+		printf("ERROR: flash area is locked\n");
+		return 1;
+	}
+
 	buf = map_physmem(addr, len, MAP_WRBACK);
 	if (!buf && addr) {
 		puts("Failed to map physical memory\n");
@@ -350,6 +356,12 @@
 		return 1;
 	}
 
+	if (flash->flash_is_unlocked &&
+	    !flash->flash_is_unlocked(flash, offset, len)) {
+		printf("ERROR: flash area is locked\n");
+		return 1;
+	}
+
 	ret = spi_flash_erase(flash, offset, size);
 	printf("SF: %zu bytes @ %#x Erased: ", (size_t)size, (u32)offset);
 	if (ret)