1 files changed, 5 insertions, 2 deletions
diff --git a/ports/stm32/flashbdev.c b/ports/stm32/flashbdev.c
index 2b633cf16..395662c8b 100644
--- a/ports/stm32/flashbdev.c
+++ b/ports/stm32/flashbdev.c
@@ -143,14 +143,17 @@ int32_t flash_bdev_ioctl(uint32_t op, uint32_t arg) {
             flash_bdev_irq_handler();
             return 0;
 
-        case BDEV_IOCTL_SYNC:
+        case BDEV_IOCTL_SYNC: {
+            uint32_t basepri = raise_irq_pri(IRQ_PRI_FLASH); // prevent cache flushing and USB access
             if (flash_flags & FLASH_FLAG_DIRTY) {
                 flash_flags |= FLASH_FLAG_FORCE_WRITE;
                 while (flash_flags & FLASH_FLAG_DIRTY) {
-                   NVIC->STIR = FLASH_IRQn;
+                    flash_bdev_irq_handler();
                 }
             }
+            restore_irq_pri(basepri);
             return 0;
+        }
     }
     return -MP_EINVAL;
 }