diff --git a/extmod/machine_spi.c b/extmod/machine_spi.c
index a7f96573a7..c951a5137c 100644
--- a/extmod/machine_spi.c
+++ b/extmod/machine_spi.c
@@ -41,28 +41,6 @@
 /******************************************************************************/
 // MicroPython bindings for generic machine.SPI
 
-STATIC mp_obj_t mp_machine_soft_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
-
-mp_obj_t mp_machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
-    // check the id argument, if given
-    if (n_args > 0) {
-        if (args[0] != MP_OBJ_NEW_SMALL_INT(-1)) {
-            #if defined(MICROPY_PY_MACHINE_SPI_MAKE_NEW)
-            // dispatch to port-specific constructor
-            extern mp_obj_t MICROPY_PY_MACHINE_SPI_MAKE_NEW(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
-            return MICROPY_PY_MACHINE_SPI_MAKE_NEW(type, n_args, n_kw, args);
-            #else
-            mp_raise_ValueError(MP_ERROR_TEXT("invalid SPI peripheral"));
-            #endif
-        }
-        --n_args;
-        ++args;
-    }
-
-    // software SPI
-    return mp_machine_soft_spi_make_new(type, n_args, n_kw, args);
-}
-
 STATIC mp_obj_t machine_spi_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
     mp_obj_base_t *s = (mp_obj_base_t *)MP_OBJ_TO_PTR(args[0]);
     mp_machine_spi_p_t *spi_p = (mp_machine_spi_p_t *)s->type->protocol;
@@ -275,7 +253,7 @@ const mp_obj_type_t mp_machine_soft_spi_type = {
     { &mp_type_type },
     .name = MP_QSTR_SoftSPI,
     .print = mp_machine_soft_spi_print,
-    .make_new = mp_machine_spi_make_new, // delegate to master constructor
+    .make_new = mp_machine_soft_spi_make_new,
     .protocol = &mp_machine_soft_spi_p,
     .locals_dict = (mp_obj_dict_t *)&mp_machine_spi_locals_dict,
 };
diff --git a/ports/esp32/mpconfigport.h b/ports/esp32/mpconfigport.h
index 00abab3afd..5bf0676b23 100644
--- a/ports/esp32/mpconfigport.h
+++ b/ports/esp32/mpconfigport.h
@@ -148,7 +148,6 @@
 #define MICROPY_PY_MACHINE_SPI              (1)
 #define MICROPY_PY_MACHINE_SPI_MSB          (0)
 #define MICROPY_PY_MACHINE_SPI_LSB          (1)
-#define MICROPY_PY_MACHINE_SPI_MAKE_NEW     machine_hw_spi_make_new
 #define MICROPY_HW_ENABLE_SDCARD            (1)
 #define MICROPY_HW_SOFTSPI_MIN_DELAY        (0)
 #define MICROPY_HW_SOFTSPI_MAX_BAUDRATE     (ets_get_cpu_frequency() * 1000000 / 200) // roughly
diff --git a/ports/esp8266/machine_hspi.c b/ports/esp8266/machine_hspi.c
index 7319194d76..55bbcf9f58 100644
--- a/ports/esp8266/machine_hspi.c
+++ b/ports/esp8266/machine_hspi.c
@@ -178,7 +178,7 @@ const mp_obj_type_t machine_hspi_type = {
     { &mp_type_type },
     .name = MP_QSTR_HSPI,
     .print = machine_hspi_print,
-    .make_new = mp_machine_spi_make_new, // delegate to master constructor
+    .make_new = machine_hspi_make_new,
     .protocol = &machine_hspi_p,
     .locals_dict = (mp_obj_dict_t *)&mp_machine_spi_locals_dict,
 };
diff --git a/ports/esp8266/mpconfigport.h b/ports/esp8266/mpconfigport.h
index 5344a98d6a..974310f84d 100644
--- a/ports/esp8266/mpconfigport.h
+++ b/ports/esp8266/mpconfigport.h
@@ -80,7 +80,6 @@
 #define MICROPY_PY_MACHINE_PULSE    (1)
 #define MICROPY_PY_MACHINE_I2C      (1)
 #define MICROPY_PY_MACHINE_SPI      (1)
-#define MICROPY_PY_MACHINE_SPI_MAKE_NEW machine_hspi_make_new
 #define MICROPY_PY_UWEBSOCKET       (1)
 #define MICROPY_PY_WEBREPL          (1)
 #define MICROPY_PY_WEBREPL_DELAY    (20)
diff --git a/ports/stm32/machine_spi.c b/ports/stm32/machine_spi.c
index cf6e96ab67..edbd500b3c 100644
--- a/ports/stm32/machine_spi.c
+++ b/ports/stm32/machine_spi.c
@@ -48,7 +48,7 @@ STATIC void machine_hard_spi_print(const mp_print_t *print, mp_obj_t self_in, mp
 mp_obj_t machine_hard_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
     enum { ARG_id, ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit, ARG_sck, ARG_mosi, ARG_miso };
     static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_id,       MP_ARG_OBJ, {.u_obj = MP_OBJ_NEW_SMALL_INT(-1)} },
+        { MP_QSTR_id,       MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 500000} },
         { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
@@ -137,7 +137,7 @@ const mp_obj_type_t machine_hard_spi_type = {
     { &mp_type_type },
     .name = MP_QSTR_SPI,
     .print = machine_hard_spi_print,
-    .make_new = mp_machine_spi_make_new, // delegate to master constructor
+    .make_new = machine_hard_spi_make_new,
     .protocol = &machine_hard_spi_p,
     .locals_dict = (mp_obj_dict_t *)&mp_machine_spi_locals_dict,
 };
diff --git a/ports/stm32/mpconfigport.h b/ports/stm32/mpconfigport.h
index 9ff4765ac2..7ea41bb6f4 100644
--- a/ports/stm32/mpconfigport.h
+++ b/ports/stm32/mpconfigport.h
@@ -186,7 +186,6 @@
 #define MICROPY_PY_MACHINE_SPI      (1)
 #define MICROPY_PY_MACHINE_SPI_MSB  (SPI_FIRSTBIT_MSB)
 #define MICROPY_PY_MACHINE_SPI_LSB  (SPI_FIRSTBIT_LSB)
-#define MICROPY_PY_MACHINE_SPI_MAKE_NEW machine_hard_spi_make_new
 #define MICROPY_HW_SOFTSPI_MIN_DELAY (0)
 #define MICROPY_HW_SOFTSPI_MAX_BAUDRATE (HAL_RCC_GetSysClockFreq() / 48)
 #define MICROPY_PY_UWEBSOCKET       (MICROPY_PY_LWIP)