diff --git a/boot/bootutil/src/bootutil_misc.c b/boot/bootutil/src/bootutil_misc.c
index 2fe08e3..031031b 100644
--- a/boot/bootutil/src/bootutil_misc.c
+++ b/boot/bootutil/src/bootutil_misc.c
@@ -310,13 +310,14 @@
 {
     uint32_t off;
     int rc;
-    uint8_t buf[8];
+    uint8_t buf[BOOT_MAX_ALIGN];
     uint8_t align;
 
     off = boot_copy_done_off(fap);
 
     align = hal_flash_align(fap->fa_device_id);
-    memset(buf, 0xFF, 8);
+    assert(align <= BOOT_MAX_ALIGN);
+    memset(buf, 0xFF, BOOT_MAX_ALIGN);
     buf[0] = 1;
 
     rc = flash_area_write(fap, off, buf, align);
@@ -332,14 +333,16 @@
 {
     uint32_t off;
     int rc;
-    uint8_t buf[8];
+    uint8_t buf[BOOT_MAX_ALIGN];
     uint8_t align;
 
     off = boot_image_ok_off(fap);
 
     align = hal_flash_align(fap->fa_device_id);
-    memset(buf, 0xFF, 8);
+    assert(align <= BOOT_MAX_ALIGN);
+    memset(buf, 0xFF, BOOT_MAX_ALIGN);
     buf[0] = 1;
+
     rc = flash_area_write(fap, off, buf, align);
     if (rc != 0) {
         return BOOT_EFLASH;
diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index 79885ae..3bdd1cc 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -39,6 +39,8 @@
 
 #define BOOT_TMPBUF_SZ  256
 
+#define BOOT_MAX_ALIGN  8
+
 /*
  * Maintain state of copy progress.
  */