diff --git a/chip/stm32/config-stm32f05x.h b/chip/stm32/config-stm32f05x.h
index 648347879a..cab7b62d50 100644
--- a/chip/stm32/config-stm32f05x.h
+++ b/chip/stm32/config-stm32f05x.h
@@ -6,7 +6,7 @@
 /* Memory mapping */
 #define CONFIG_FLASH_SIZE (64 * 1024)
 #define CONFIG_FLASH_BANK_SIZE  0x1000
-#define CONFIG_FLASH_ERASE_SIZE 0x0800  /* erase bank size */
+#define CONFIG_FLASH_ERASE_SIZE 0x0400  /* erase bank size */
 #define CONFIG_FLASH_WRITE_SIZE 0x0002  /* minimum write size */
 
 /* No page mode on STM32F, so no benefit to larger write sizes */