diff --git a/Makefile b/Makefile
index c6725a1..02c67a4 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,20 @@
 TARGET = lfs
 
+ifndef OS
 OS := $(shell uname -s)
+endif
 
+ifndef CC
 CC = cc
+endif
+
+ifndef AR
 AR = ar
+endif
+
+ifndef SIZE
 SIZE = size
+endif
 
 SRC += $(wildcard *.c littlefs/*.c)
 OBJ := $(SRC:.c=.o)
@@ -28,6 +38,10 @@ override CFLAGS += -DLFS_MULTIVERSION
 # enable migrate support in littlefs
 override CFLAGS += -DLFS_MIGRATE
 
+ifdef DEFAULT_LFS_BLOCK_SIZE
+override CFLAGS += -DDEFAULT_LFS_BLOCK_SIZE=$(DEFAULT_LFS_BLOCK_SIZE)
+endif
+
 override LFLAGS += -lfuse
 
 ifeq ($(OS), FreeBSD)
diff --git a/lfs_fuse_bd.c b/lfs_fuse_bd.c
index d01a21f..a58cb2e 100644
--- a/lfs_fuse_bd.c
+++ b/lfs_fuse_bd.c
@@ -30,6 +30,13 @@ int lfs_fuse_bd_create(struct lfs_config *cfg, const char *path) {
     }
     cfg->context = (void*)(intptr_t)fd;
 
+    // use sector size from build override
+#ifdef DEFAULT_LFS_BLOCK_SIZE
+    if (!cfg->block_size) {
+        cfg->block_size = DEFAULT_LFS_BLOCK_SIZE;
+    }
+#endif
+
     // get sector size
     if (!cfg->block_size) {
         long ssize;