diff --git a/arch/arm/src/stm32/stm32_dac.c b/arch/arm/src/stm32/stm32_dac.c
index 72ff260b1f9..bf6547d2156 100644
--- a/arch/arm/src/stm32/stm32_dac.c
+++ b/arch/arm/src/stm32/stm32_dac.c
@@ -984,9 +984,11 @@ static void dac_txint(FAR struct dac_dev_s *dev, bool enable)
  *
  ****************************************************************************/
 
+#ifdef HAVE_DMA
 static void dac_dmatxcallback(DMA_HANDLE handle, uint8_t isr, FAR void *arg)
 {
 }
+#endif
 
 /****************************************************************************
  * Name: dac_send
@@ -1114,6 +1116,7 @@ static int dac_ioctl(FAR struct dac_dev_s *dev, int cmd, unsigned long arg)
         }
     }
 
+  UNUSED(chan);
   return ret;
 }
 
diff --git a/drivers/mtd/mx25rxx.c b/drivers/mtd/mx25rxx.c
index b4682528438..984df6b7aab 100644
--- a/drivers/mtd/mx25rxx.c
+++ b/drivers/mtd/mx25rxx.c
@@ -233,7 +233,9 @@ static void mx25rxx_write_enable(FAR struct mx25rxx_dev_s *dev, bool enable);
 static int mx25rxx_write_page(struct mx25rxx_dev_s *priv,
                        FAR const uint8_t *buffer, off_t address, size_t buflen);
 static int mx25rxx_erase_sector(struct mx25rxx_dev_s *priv, off_t sector);
+#if 0 /* FIXME:  Not used */
 static int mx25rxx_erase_block(struct mx25rxx_dev_s *priv, off_t block);
+#endif
 static int mx25rxx_erase_chip(struct mx25rxx_dev_s *priv);
 
 #ifdef CONFIG_MX25RXX_SECTOR512
@@ -460,6 +462,7 @@ int mx25rxx_erase_sector(struct mx25rxx_dev_s *priv, off_t sector)
   return OK;
 }
 
+#if 0 /* FIXME:  Not used */
 int mx25rxx_erase_block(struct mx25rxx_dev_s *priv, off_t block)
 {
   uint8_t status;
@@ -483,6 +486,7 @@ int mx25rxx_erase_block(struct mx25rxx_dev_s *priv, off_t block)
 
   return OK;
 }
+#endif
 
 int mx25rxx_erase_chip(struct mx25rxx_dev_s *priv)
 {