diff --git a/arch/xtensa/include/esp32/irq.h b/arch/xtensa/include/esp32/irq.h
index 4c8e6c47ca..a3cbab72c1 100644
--- a/arch/xtensa/include/esp32/irq.h
+++ b/arch/xtensa/include/esp32/irq.h
@@ -378,7 +378,7 @@
 #define ESP32_CPUINT_NEDGEPERIPHS   4
 #define EPS32_CPUINT_EDGESET        0x50400400
 
-#define ESP32_CPUINT_NNMIPERIPHS    4
+#define ESP32_CPUINT_NNMIPERIPHS    1
 #define EPS32_CPUINT_NMISET         0x00004000
 
 #define ESP32_CPUINT_TIMER0         6
@@ -388,11 +388,11 @@
 #define ESP32_CPUINT_TIMER2         16
 #define ESP32_CPUINT_SOFTWARE1      29
 
-#define ESP32_CPUINT_NINTERNAL      5
+#define ESP32_CPUINT_NINTERNAL      6
 
 #define ESP32_CPUINT_MAX            31
-#define EPS32_CPUINT_PERIPHSET      0xdffe6f3f
-#define EPS32_CPUINT_INTERNALSET    0x200180c0
+#define EPS32_CPUINT_PERIPHSET      0xdffe773f
+#define EPS32_CPUINT_INTERNALSET    0x200188c0
 
 /* Priority 1:   0-10, 12-13, 17-18    (15)
  * Priority 2:   19-21                 (3)
diff --git a/arch/xtensa/src/esp32/esp32_cpuint.c b/arch/xtensa/src/esp32/esp32_cpuint.c
index 571c7fd074..2324e7fe3c 100644
--- a/arch/xtensa/src/esp32/esp32_cpuint.c
+++ b/arch/xtensa/src/esp32/esp32_cpuint.c
@@ -165,9 +165,11 @@ static uint32_t g_intenable[1];
 
 #endif
 
-/* Bitsets for free, unallocated CPU interrupts */
+/* Bitsets for free, unallocated CPU interrupts available to peripheral
+ * devices.
+ */
 
-static uint32_t g_free_cpuints = 0xffffffff;
+static uint32_t g_free_cpuints = EPS32_CPUINT_PERIPHSET;
 
 /* Bitsets for each interrupt priority 1-5 */
 
@@ -188,7 +190,9 @@ static const uint32_t g_priority[5] =
  * Name:  esp32_alloc_cpuint
  *
  * Description:
- *   Allocate a CPU interrupt
+ *   Allocate a CPU interrupt for a peripheral device.  This function will
+ *   not allocate any of the pre-allocated CPU interrupts for internal
+ *   devices.
  *
  * Input Parameters:
  *   intmask - mask of candidate CPU interrupts.  The CPU interrupt will be
@@ -224,7 +228,7 @@ int esp32_alloc_cpuint(uint32_t intmask)
        */
 
       for (cpuint = 0, bitmask = 0xff;
-           cpuint <= ESP32_CPUINT_MAX;
+           cpuint <= ESP32_CPUINT_MAX && (intset & bitmask) == 0;
            cpuint += 8, bitmask <<= 8);
 
       /* Search for an unallocated CPU interrupt number in the remaining
diff --git a/arch/xtensa/src/esp32/esp32_serial.c b/arch/xtensa/src/esp32/esp32_serial.c
index 34846e89e8..36c66dcc09 100644
--- a/arch/xtensa/src/esp32/esp32_serial.c
+++ b/arch/xtensa/src/esp32/esp32_serial.c
@@ -455,8 +455,8 @@ static void esp32_disableallints(struct esp32_dev_s *priv, uint32_t *intena)
 
 static int esp32_setup(struct uart_dev_s *dev)
 {
-  struct esp32_dev_s *priv = (struct esp32_dev_s *)dev->priv;
 #ifndef CONFIG_SUPPRESS_UART_CONFIG
+  struct esp32_dev_s *priv = (struct esp32_dev_s *)dev->priv;
   uint32_t clkdiv;
   uint32_t regval;
   uint32_t conf0;
@@ -655,7 +655,9 @@ static int esp32_attach(struct uart_dev_s *dev)
   priv->cpuint = esp32_alloc_levelint(1);
   if (priv->cpuint < 0)
     {
-      ret = priv->cpuint;
+      /* Failed to allocate a CPU interrupt of this type */
+
+      return priv->cpuint;
     }
 
   /* Set up to receive peripheral interrupts on the current CPU */