diff --git a/cc3200/mods/modwlan.c b/cc3200/mods/modwlan.c
index f5a7c962bd..1efecf41a6 100644
--- a/cc3200/mods/modwlan.c
+++ b/cc3200/mods/modwlan.c
@@ -657,8 +657,9 @@ STATIC mp_obj_t wlan_init_helper(mp_uint_t n_args, const mp_obj_t *pos_args, mp_
         nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
     }
 
-    // Force the channel to be between 1-11
-    uint8_t channel = args[4].u_int > 0 ? args[4].u_int % 12 : 1;
+    // force the channel to be between 1-11
+    uint8_t channel = args[4].u_int;
+    channel = (channel > 0 && channel != 12) ? channel % 12 : 1;
 
     if (MODWLAN_OK != wlan_sl_enable (args[0].u_int, ssid, ssid_len, args[2].u_int, key, key_len, channel)) {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_operation_failed));
@@ -700,7 +701,7 @@ STATIC mp_obj_t wlan_make_new (mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_k
     mp_arg_check_num(n_args, n_kw, 0, MP_ARRAY_SIZE(wlan_init_args), true);
 
     if (n_args > 0) {
-        // Get the mode
+        // get the mode
         SlWlanMode_t mode = mp_obj_get_int(args[0]);
         if (mode == ROLE_AP) {
             // start the peripheral
@@ -708,7 +709,7 @@ STATIC mp_obj_t wlan_make_new (mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_k
             mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
             wlan_init_helper(n_args, args, &kw_args);
         }
-        // TODO: Only STA mode supported for the moment. What if P2P?
+        // TODO only STA mode supported for the moment. What if P2P?
         else if (n_args == 1) {
             if (MODWLAN_OK != wlan_sl_enable (mode, NULL, 0, 0, NULL, 0, 0)) {
                 nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_operation_failed));
@@ -717,12 +718,9 @@ STATIC mp_obj_t wlan_make_new (mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_k
         else {
             nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, mpexception_num_type_invalid_arguments));
         }
-    } else if (wlan_obj.mode < 0) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, mpexception_num_type_invalid_arguments));
     }
 
     wlan_obj.base.type = (mp_obj_type_t*)&mod_network_nic_type_wlan;
-
     return &wlan_obj;
 }
 
diff --git a/cc3200/mods/pybi2c.c b/cc3200/mods/pybi2c.c
index 7d4f70e867..1b9c6ca16c 100644
--- a/cc3200/mods/pybi2c.c
+++ b/cc3200/mods/pybi2c.c
@@ -280,6 +280,11 @@ STATIC mp_obj_t pyb_i2c_init_helper(pyb_i2c_obj_t *self, mp_uint_t n_args, const
     mp_arg_val_t vals[PYB_I2C_INIT_NUM_ARGS];
     mp_arg_parse_all(n_args, args, kw_args, PYB_I2C_INIT_NUM_ARGS, pyb_i2c_init_args, vals);
 
+    // verify that mode is master
+    if (vals[0].u_int != PYBI2C_MASTER) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+    }
+
     // make sure the baudrate is between the valid range
     self->baudrate = MIN(MAX(vals[1].u_int, PYBI2C_MIN_BAUD_RATE_HZ), PYBI2C_MAX_BAUD_RATE_HZ);
 
@@ -303,11 +308,6 @@ STATIC mp_obj_t pyb_i2c_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n
     // check arguments
     mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
 
-    // work out the i2c bus id
-    if (mp_obj_get_int(args[0]) != 1) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_resource_not_avaliable));
-    }
-
     // setup the object
     pyb_i2c_obj_t *self = &pyb_i2c_obj;
     self->base.type = &pyb_i2c_type;
diff --git a/cc3200/mods/pybpin.c b/cc3200/mods/pybpin.c
index e4661641f1..64a1250284 100644
--- a/cc3200/mods/pybpin.c
+++ b/cc3200/mods/pybpin.c
@@ -367,32 +367,35 @@ STATIC mp_obj_t pin_obj_init_helper(pin_obj_t *self, mp_uint_t n_args, const mp_
     // get the af
     uint af = args[0].u_int;
     if (af < PIN_MODE_0 || af > PIN_MODE_15) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+        goto invalid_args;
     }
     // get the io mode
     uint mode = args[1].u_int;
     // checking the mode only makes sense if af == GPIO
     if (af == PIN_MODE_0) {
         if (mode != GPIO_DIR_MODE_IN && mode != GPIO_DIR_MODE_OUT) {
-            nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+            goto invalid_args;
         }
     }
     // get the type
     uint type = args[2].u_int;
     if (type != PIN_TYPE_STD && type != PIN_TYPE_STD_PU && type != PIN_TYPE_STD_PD &&
             type != PIN_TYPE_OD && type != PIN_TYPE_OD_PU && type != PIN_TYPE_OD_PD) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+        goto invalid_args;
     }
     // get the strenght
     uint strength = args[3].u_int;
     if (strength != PIN_STRENGTH_2MA && strength != PIN_STRENGTH_4MA && strength != PIN_STRENGTH_6MA) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+        goto invalid_args;
     }
 
     // configure the pin as requested
     pin_config (self, af, mode, type, strength);
 
     return mp_const_none;
+
+invalid_args:
+    nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
 }
 
 /// \method print()
@@ -560,7 +563,7 @@ STATIC mp_obj_t pin_callback (mp_uint_t n_args, const mp_obj_t *pos_args, mp_map
         uint intmode = args[0].u_int;
         if (intmode != GPIO_FALLING_EDGE && intmode != GPIO_RISING_EDGE && intmode != GPIO_BOTH_EDGES &&
             intmode != GPIO_LOW_LEVEL && intmode != GPIO_HIGH_LEVEL) {
-            nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+            goto invalid_args;
         }
 
         uint pwrmode = args[4].u_int;
diff --git a/cc3200/mods/pybspi.c b/cc3200/mods/pybspi.c
index ebd8159e41..3c8ff5b170 100644
--- a/cc3200/mods/pybspi.c
+++ b/cc3200/mods/pybspi.c
@@ -201,6 +201,11 @@ STATIC mp_obj_t pyb_spi_init_helper(pyb_spi_obj_t *self, mp_uint_t n_args, const
     mp_arg_val_t args[MP_ARRAY_SIZE(pybspi_init_args)];
     mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(pybspi_init_args), pybspi_init_args, args);
 
+    // verify that mode is master
+    if (args[0].u_int != SPI_MODE_MASTER) {
+        goto invalid_args;
+    }
+
     uint bits;
     switch (args[2].u_int) {
     case 8:
@@ -213,7 +218,7 @@ STATIC mp_obj_t pyb_spi_init_helper(pyb_spi_obj_t *self, mp_uint_t n_args, const
         bits = SPI_WL_32;
         break;
     default:
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+        goto invalid_args;
         break;
     }
 
@@ -240,7 +245,7 @@ STATIC mp_obj_t pyb_spi_init_helper(pyb_spi_obj_t *self, mp_uint_t n_args, const
 
     uint nss = args[5].u_int;
     if (nss != SPI_CS_ACTIVELOW && nss != SPI_CS_ACTIVEHIGH) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
+        goto invalid_args;
     }
 
     // build the configuration
@@ -258,6 +263,9 @@ STATIC mp_obj_t pyb_spi_init_helper(pyb_spi_obj_t *self, mp_uint_t n_args, const
     pybsleep_add((const mp_obj_t)self, (WakeUpCB_t)pybspi_init);
 
     return mp_const_none;
+
+invalid_args:
+    nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, mpexception_value_invalid_arguments));
 }
 
 /// \classmethod \constructor(bus, ...)
@@ -272,11 +280,6 @@ STATIC mp_obj_t pyb_spi_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n
     // check arguments
     mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
 
-    // work out the spi bus id
-    if (mp_obj_get_int(args[0]) != 1) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_resource_not_avaliable));
-    }
-
     pyb_spi_obj_t *self = &pyb_spi_obj;
     self->base.type = &pyb_spi_type;
 
diff --git a/cc3200/mods/pybuart.c b/cc3200/mods/pybuart.c
index b4fca81fa6..4586cb8c56 100644
--- a/cc3200/mods/pybuart.c
+++ b/cc3200/mods/pybuart.c
@@ -540,7 +540,7 @@ STATIC mp_obj_t pyb_uart_writechar(mp_obj_t self_in, mp_obj_t char_in) {
 
     // send the character
     if (!uart_tx_char(self, data)) {
-        nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(ETIMEDOUT)));
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_operation_failed));
     }
 
     return mp_const_none;
@@ -624,7 +624,7 @@ STATIC mp_uint_t pyb_uart_write(mp_obj_t self_in, const void *buf_in, mp_uint_t
 
     // write the data
     if (!uart_tx_strn(self, buf, size)) {
-        nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(ETIMEDOUT)));
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, mpexception_os_operation_failed));
     }
     return size;
 }