diff --git a/boot/espressif/include/flash_map_backend/flash_map_backend.h b/boot/espressif/include/flash_map_backend/flash_map_backend.h
index fcbdc9f..b56bcbc 100644
--- a/boot/espressif/include/flash_map_backend/flash_map_backend.h
+++ b/boot/espressif/include/flash_map_backend/flash_map_backend.h
@@ -69,7 +69,7 @@
                      uint32_t off, uint32_t len);
 
 //! Returns this `flash_area`s alignment
-size_t flash_area_align(const struct flash_area *area);
+uint32_t flash_area_align(const struct flash_area *area);
 //! Returns the value read from an erased flash area byte
 uint8_t flash_area_erased_val(const struct flash_area *area);
 
diff --git a/boot/espressif/port/esp_mcuboot.c b/boot/espressif/port/esp_mcuboot.c
index 556e422..4dd03b9 100644
--- a/boot/espressif/port/esp_mcuboot.c
+++ b/boot/espressif/port/esp_mcuboot.c
@@ -239,7 +239,7 @@
     return 0;
 }
 
-size_t flash_area_align(const struct flash_area *area)
+uint32_t flash_area_align(const struct flash_area *area)
 {
     return 4;
 }