diff --git a/arch/xtensa/src/esp32/esp32_spiflash.c b/arch/xtensa/src/esp32/esp32_spiflash.c
index cde3e6a3c75..96c21ca7494 100644
--- a/arch/xtensa/src/esp32/esp32_spiflash.c
+++ b/arch/xtensa/src/esp32/esp32_spiflash.c
@@ -594,7 +594,7 @@ static void IRAM_ATTR spiflash_flushmapped(size_t start, size_t size)
   uint32_t addr;
   uint32_t page;
 
-  page_start = MMU_ALIGNDOWN_SIZE(size);
+  page_start = MMU_ALIGNDOWN_SIZE(start);
   size += (start - page_start);
   size = MMU_ALIGNUP_SIZE(size);