diff --git a/hw/arm/stm32f205_soc.c b/hw/arm/stm32f205_soc.c
index 627fd446f5..2de56275b7 100644
--- a/hw/arm/stm32f205_soc.c
+++ b/hw/arm/stm32f205_soc.c
@@ -93,12 +93,10 @@ static void stm32f205_soc_realize(DeviceState *dev_soc, Error **errp)
     MemoryRegion *flash = g_new(MemoryRegion, 1);
     MemoryRegion *flash_alias = g_new(MemoryRegion, 1);
 
-    memory_region_init_ram(flash, NULL, "STM32F205.flash", FLASH_SIZE,
+    memory_region_init_rom(flash, NULL, "STM32F205.flash", FLASH_SIZE,
                            &error_fatal);
     memory_region_init_alias(flash_alias, NULL, "STM32F205.flash.alias",
                              flash, 0, FLASH_SIZE);
-
-    memory_region_set_readonly(flash, true);
     memory_region_set_readonly(flash_alias, true);
 
     memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, flash);
diff --git a/hw/arm/stm32f405_soc.c b/hw/arm/stm32f405_soc.c
index 9bcad97853..b8fca13f95 100644
--- a/hw/arm/stm32f405_soc.c
+++ b/hw/arm/stm32f405_soc.c
@@ -95,7 +95,7 @@ static void stm32f405_soc_realize(DeviceState *dev_soc, Error **errp)
     Error *err = NULL;
     int i;
 
-    memory_region_init_ram(&s->flash, NULL, "STM32F405.flash", FLASH_SIZE,
+    memory_region_init_rom(&s->flash, NULL, "STM32F405.flash", FLASH_SIZE,
                            &err);
     if (err != NULL) {
         error_propagate(errp, err);
@@ -103,8 +103,6 @@ static void stm32f405_soc_realize(DeviceState *dev_soc, Error **errp)
     }
     memory_region_init_alias(&s->flash_alias, NULL, "STM32F405.flash.alias",
                              &s->flash, 0, FLASH_SIZE);
-
-    memory_region_set_readonly(&s->flash, true);
     memory_region_set_readonly(&s->flash_alias, true);
 
     memory_region_add_subregion(system_memory, FLASH_BASE_ADDRESS, &s->flash);