diff --git a/ports/mimxrt10xx/common-hal/busio/I2C.c b/ports/mimxrt10xx/common-hal/busio/I2C.c
index 0bb7dcc6c6..0ac3678680 100644
--- a/ports/mimxrt10xx/common-hal/busio/I2C.c
+++ b/ports/mimxrt10xx/common-hal/busio/I2C.c
@@ -27,15 +27,32 @@
 
 #include <stdio.h>
 
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/microcontroller/__init__.h"
 #include "shared-bindings/busio/I2C.h"
 #include "py/mperrno.h"
 #include "py/runtime.h"
 #include "periph.h"
 
 #include "fsl_lpi2c.h"
+#include "fsl_gpio.h"
 
 #define I2C_CLOCK_FREQ (CLOCK_GetFreq(kCLOCK_Usb1PllClk) / 8 / (1+CLOCK_GetDiv(kCLOCK_Lpi2cDiv)))
+#define IOMUXC_SW_MUX_CTL_PAD_MUX_MODE_ALT5 5U
 
+//arrays use 0 based numbering: I2C1 is stored at index 0
+#define MAX_I2C 4
+STATIC bool reserved_i2c[MAX_I2C];
+STATIC bool never_reset_i2c[MAX_I2C];
+
+void i2c_reset(void) {
+    for(uint i = 0; i < MP_ARRAY_SIZE(mcu_i2c_banks); i++) {
+        if (!never_reset_i2c[i]) {
+            reserved_i2c[i] = false;
+            LPI2C_MasterDeinit(mcu_i2c_banks[i]);
+        }
+    }
+}
 
 static void config_periph_pin(const mcu_periph_obj_t *periph) {
     IOMUXC_SetPinMux(
@@ -56,11 +73,49 @@ static void config_periph_pin(const mcu_periph_obj_t *periph) {
             | IOMUXC_SW_PAD_CTL_PAD_SRE(0));
 }
 
+static void i2c_check_pin_config(const mcu_pin_obj_t *pin, uint32_t pull)
+{
+    IOMUXC_SetPinConfig(0, 0, 0, 0, pin->cfg_reg,
+        IOMUXC_SW_PAD_CTL_PAD_HYS(1)
+            | IOMUXC_SW_PAD_CTL_PAD_PUS(0) // Pulldown
+            | IOMUXC_SW_PAD_CTL_PAD_PUE(pull) // 0=nopull (keeper), 1=pull
+            | IOMUXC_SW_PAD_CTL_PAD_PKE(1)
+            | IOMUXC_SW_PAD_CTL_PAD_ODE(0)
+            | IOMUXC_SW_PAD_CTL_PAD_SPEED(2)
+            | IOMUXC_SW_PAD_CTL_PAD_DSE(1)
+            | IOMUXC_SW_PAD_CTL_PAD_SRE(0));
+}
+
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
         const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
 
-    const uint32_t sda_count = sizeof(mcu_i2c_sda_list) / sizeof(mcu_periph_obj_t);
-    const uint32_t scl_count = sizeof(mcu_i2c_scl_list) / sizeof(mcu_periph_obj_t);
+    #if CIRCUITPY_REQUIRE_I2C_PULLUPS
+    // Test that the pins are in a high state. (Hopefully indicating they are pulled up.)
+    IOMUXC_SetPinMux(sda->mux_reg, IOMUXC_SW_MUX_CTL_PAD_MUX_MODE_ALT5, 0, 0, 0, 0);
+    IOMUXC_SetPinMux(scl->mux_reg, IOMUXC_SW_MUX_CTL_PAD_MUX_MODE_ALT5, 0, 0, 0, 0);
+    i2c_check_pin_config(sda, 1);
+    i2c_check_pin_config(scl, 1);
+    const gpio_pin_config_t check_config = { kGPIO_DigitalInput, 0, kGPIO_NoIntmode };
+    GPIO_PinInit(sda->gpio, sda->number, &check_config);
+    GPIO_PinInit(scl->gpio, scl->number, &check_config);
+
+    common_hal_mcu_delay_us(10);
+
+    i2c_check_pin_config(sda, 0);
+    i2c_check_pin_config(scl, 0);
+
+    // We must pull up within 3us to achieve 400khz.
+    common_hal_mcu_delay_us(3);
+
+    if( !GPIO_PinRead(sda->gpio, sda->number) || !GPIO_PinRead(scl->gpio, scl->number)) {
+        common_hal_reset_pin(sda);
+        common_hal_reset_pin(scl);
+        mp_raise_RuntimeError(translate("SDA or SCL needs a pull up"));
+    }
+    #endif
+
+    const uint32_t sda_count = MP_ARRAY_SIZE(mcu_i2c_sda_list);
+    const uint32_t scl_count = MP_ARRAY_SIZE(mcu_i2c_scl_list);
 
     for (uint32_t i = 0; i < sda_count; ++i) {
         if (mcu_i2c_sda_list[i].pin != sda)
@@ -73,21 +128,21 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
             if (mcu_i2c_scl_list[j].bank_idx != mcu_i2c_sda_list[i].bank_idx)
                 continue;
 
-            self->sda_pin = &mcu_i2c_sda_list[i];
-            self->scl_pin = &mcu_i2c_scl_list[j];
+            self->sda = &mcu_i2c_sda_list[i];
+            self->scl = &mcu_i2c_scl_list[j];
 
             break;
         }
     }
 
-    if(self->sda_pin == NULL || self->scl_pin == NULL) {
+    if(self->sda == NULL || self->scl == NULL) {
         mp_raise_RuntimeError(translate("Invalid I2C pin selection"));
     } else {
-        self->i2c = mcu_i2c_banks[self->sda_pin->bank_idx - 1];
+        self->i2c = mcu_i2c_banks[self->sda->bank_idx - 1];
     }
 
-    config_periph_pin(self->sda_pin);
-    config_periph_pin(self->scl_pin);
+    config_periph_pin(self->sda);
+    config_periph_pin(self->scl);
 
     lpi2c_master_config_t config = { 0 };
     LPI2C_MasterGetDefaultConfig(&config);
@@ -96,34 +151,35 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
 
     LPI2C_MasterInit(self->i2c, &config, I2C_CLOCK_FREQ);
 
-#if CIRCUITPY_REQUIRE_I2C_PULLUPS
-//    if (!gpio_get_pin_level(sda->number) || !gpio_get_pin_level(scl->number)) {
-//        reset_pin_number(sda->number);
-//        reset_pin_number(scl->number);
-//        mp_raise_RuntimeError(translate("SDA or SCL needs a pull up"));
-//    }
-#endif
+    claim_pin(self->sda->pin);
+    claim_pin(self->scl->pin);
+}
 
-    claim_pin(self->sda_pin->pin);
-    claim_pin(self->scl_pin->pin);
+void common_hal_busio_i2c_never_reset(busio_i2c_obj_t *self) {
+    never_reset_i2c[self->sda->bank_idx - 1] = true;
+
+    common_hal_never_reset_pin(self->sda->pin);
+    common_hal_never_reset_pin(self->scl->pin);
 }
 
 bool common_hal_busio_i2c_deinited(busio_i2c_obj_t *self) {
-    return self->sda_pin == NULL;
+    return self->sda == NULL;
 }
 
 void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
     if (common_hal_busio_i2c_deinited(self)) {
         return;
     }
+    reserved_i2c[self->sda->bank_idx - 1] = false;
+    never_reset_i2c[self->sda->bank_idx - 1] = false;
 
     LPI2C_MasterDeinit(self->i2c);
 
-//    reset_pin_number(self->sda_pin);
-//    reset_pin_number(self->scl_pin);
+    common_hal_reset_pin(self->sda->pin);
+    common_hal_reset_pin(self->scl->pin);
 
-    self->sda_pin = NULL;
-    self->scl_pin = NULL;
+    self->sda = NULL;
+    self->scl = NULL;
 }
 
 bool common_hal_busio_i2c_probe(busio_i2c_obj_t *self, uint8_t addr) {
@@ -183,10 +239,3 @@ uint8_t common_hal_busio_i2c_read(busio_i2c_obj_t *self, uint16_t addr,
 
     return MP_EIO;
 }
-
-void common_hal_busio_i2c_never_reset(busio_i2c_obj_t *self) {
-//    never_reset_sercom(self->i2c_desc.device.hw);
-//
-//    never_reset_pin_number(self->scl_pin);
-//    never_reset_pin_number(self->sda_pin);
-}
diff --git a/ports/mimxrt10xx/common-hal/busio/I2C.h b/ports/mimxrt10xx/common-hal/busio/I2C.h
index 924e108116..789f01a5f5 100644
--- a/ports/mimxrt10xx/common-hal/busio/I2C.h
+++ b/ports/mimxrt10xx/common-hal/busio/I2C.h
@@ -37,8 +37,8 @@ typedef struct {
     mp_obj_base_t base;
     LPI2C_Type *i2c;
     bool has_lock;
-    const mcu_periph_obj_t *scl_pin;
-    const mcu_periph_obj_t *sda_pin;
+    const mcu_periph_obj_t *scl;
+    const mcu_periph_obj_t *sda;
 } busio_i2c_obj_t;
 
 #endif // MICROPY_INCLUDED_MIMXRT10XX_COMMON_HAL_BUSIO_I2C_H
diff --git a/ports/mimxrt10xx/common-hal/busio/SPI.c b/ports/mimxrt10xx/common-hal/busio/SPI.c
index 54c8d001db..23e2761143 100644
--- a/ports/mimxrt10xx/common-hal/busio/SPI.c
+++ b/ports/mimxrt10xx/common-hal/busio/SPI.c
@@ -25,6 +25,8 @@
  * THE SOFTWARE.
  */
 
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/microcontroller/__init__.h"
 #include "shared-bindings/busio/SPI.h"
 #include "py/mperrno.h"
 #include "py/runtime.h"
@@ -34,6 +36,8 @@
 
 #include <stdio.h>
 
+#define LPSPI_MASTER_CLK_FREQ (CLOCK_GetFreq(kCLOCK_Usb1PllPfd0Clk) / (CLOCK_GetDiv(kCLOCK_LpspiDiv) + 1))
+
 //arrays use 0 based numbering: SPI1 is stored at index 0
 #define MAX_SPI 4
 STATIC bool reserved_spi[MAX_SPI];
@@ -58,11 +62,12 @@ STATIC void config_periph_pin(const mcu_periph_obj_t *periph) {
             | IOMUXC_SW_PAD_CTL_PAD_SRE(0));
 }
 
-#define LPSPI_MASTER_CLK_FREQ (CLOCK_GetFreq(kCLOCK_Usb1PllPfd0Clk) / (CLOCK_GetDiv(kCLOCK_LpspiDiv) + 1))
-
 void spi_reset(void) {
-    for (int i = 0; i < MAX_SPI; i++) {
-        reserved_spi[i] = false;
+    for (uint i = 0; i < MP_ARRAY_SIZE(mcu_spi_banks); i++) {
+        if (!never_reset_spi[i]) {
+            reserved_spi[i] = false;
+            LPSPI_Deinit(mcu_spi_banks[i]);
+        }
     }
 }
 
@@ -192,7 +197,14 @@ void common_hal_busio_spi_construct(busio_spi_obj_t *self,
 }
 
 void common_hal_busio_spi_never_reset(busio_spi_obj_t *self) {
-    // TODO
+    never_reset_spi[self->clock->bank_idx - 1] = true;
+    common_hal_never_reset_pin(self->clock->pin);
+    if (self->mosi != NULL) {
+        common_hal_never_reset_pin(self->mosi->pin);
+    }
+    if (self->miso != NULL) {
+        common_hal_never_reset_pin(self->miso->pin);
+    }
 }
 
 bool common_hal_busio_spi_deinited(busio_spi_obj_t *self) {
@@ -203,8 +215,20 @@ void common_hal_busio_spi_deinit(busio_spi_obj_t *self) {
     if (common_hal_busio_spi_deinited(self)) {
         return;
     }
+    LPSPI_Deinit(self->spi);
+    reserved_spi[self->clock->bank_idx - 1] = false;
+    never_reset_spi[self->clock->bank_idx - 1] = false;
 
+    common_hal_reset_pin(self->clock->pin);
+    if (self->mosi != NULL) {
+        common_hal_reset_pin(self->mosi->pin);
+    }
+    if (self->miso != NULL) {
+        common_hal_reset_pin(self->miso->pin);
+    }
     self->clock = NULL;
+    self->mosi = NULL;
+    self->miso = NULL;
 }
 
 bool common_hal_busio_spi_configure(busio_spi_obj_t *self,
diff --git a/ports/mimxrt10xx/common-hal/busio/UART.c b/ports/mimxrt10xx/common-hal/busio/UART.c
index 015b0188f4..463c404f9c 100644
--- a/ports/mimxrt10xx/common-hal/busio/UART.c
+++ b/ports/mimxrt10xx/common-hal/busio/UART.c
@@ -25,6 +25,7 @@
  * THE SOFTWARE.
  */
 
+#include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/microcontroller/__init__.h"
 #include "shared-bindings/busio/UART.h"
 
@@ -73,6 +74,13 @@ void LPUART_UserCallback(LPUART_Type *base, lpuart_handle_t *handle, status_t st
     }
 }
 
+void uart_reset(void) {
+    for(uint i = 0; i < MP_ARRAY_SIZE(mcu_uart_banks); i++) {
+        reserved_uart[i] = false;
+        LPUART_Deinit(mcu_uart_banks[i]);
+    }
+}
+
 void common_hal_busio_uart_construct(busio_uart_obj_t *self,
         const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx,
         const mcu_pin_obj_t * rts, const mcu_pin_obj_t * cts,
@@ -278,13 +286,21 @@ void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
     if (common_hal_busio_uart_deinited(self)) {
         return;
     }
-
+    if (self->rx) {
+        reserved_uart[self->rx->bank_idx - 1] = false;
+    } else {
+        reserved_uart[self->tx->bank_idx - 1] = false;
+    }
+    
     LPUART_Deinit(self->uart);
-
     gc_free(self->ringbuf);
 
-//    reset_pin_number(self->rx);
-//    reset_pin_number(self->tx);
+    if (self->rx) {
+        common_hal_reset_pin(self->rx->pin);
+    }
+    if (self->tx) {
+        common_hal_reset_pin(self->tx->pin);
+    }
 
     self->rx = NULL;
     self->tx = NULL;
diff --git a/ports/mimxrt10xx/common-hal/microcontroller/Pin.c b/ports/mimxrt10xx/common-hal/microcontroller/Pin.c
index e75df6e609..233e66006b 100644
--- a/ports/mimxrt10xx/common-hal/microcontroller/Pin.c
+++ b/ports/mimxrt10xx/common-hal/microcontroller/Pin.c
@@ -5,6 +5,7 @@
  *
  * Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
  * Copyright (c) 2019 Artur Pacholec
+ * Copyright (c) 2020 Lucian Copeland for Adafruit Industries
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.c b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.c
index 2fed6dfc61..3e2c6972b0 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.c
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.c
@@ -29,7 +29,7 @@
 #include "py/mphal.h"
 #include "mimxrt10xx/periph.h"
 
-LPI2C_Type *mcu_i2c_banks[] = { LPI2C1, LPI2C2 };
+LPI2C_Type *mcu_i2c_banks[2] = { LPI2C1, LPI2C2 };
 
 const mcu_periph_obj_t mcu_i2c_sda_list[8] = {
     PERIPH_PIN(1, 0, kIOMUXC_LPI2C1_SDA_SELECT_INPUT, 0, &pin_GPIO_AD_13),
@@ -55,7 +55,7 @@ const mcu_periph_obj_t mcu_i2c_scl_list[8] = {
     PERIPH_PIN(2, 3, kIOMUXC_LPI2C2_SCL_SELECT_INPUT, 3, &pin_GPIO_10),
 };
 
-LPSPI_Type *mcu_spi_banks[] = { LPSPI1, LPSPI2 };
+LPSPI_Type *mcu_spi_banks[2] = { LPSPI1, LPSPI2 };
 
 const mcu_periph_obj_t mcu_spi_sck_list[4] = {
     PERIPH_PIN(1, 0, kIOMUXC_LPSPI1_SCK_SELECT_INPUT, 0, &pin_GPIO_AD_06),
@@ -81,7 +81,7 @@ const mcu_periph_obj_t mcu_spi_miso_list[4] = {
     PERIPH_PIN(2, 1, kIOMUXC_LPSPI2_SDI_SELECT_INPUT, 1, &pin_GPIO_SD_09),
 };
 
-LPUART_Type *mcu_uart_banks[] = { LPUART1, LPUART2, LPUART3, LPUART4 };
+LPUART_Type *mcu_uart_banks[4] = { LPUART1, LPUART2, LPUART3, LPUART4 };
 
 const mcu_periph_obj_t mcu_uart_rx_list[9] = {
     PERIPH_PIN(1, 2, kIOMUXC_LPUART1_RXD_SELECT_INPUT, 0, &pin_GPIO_SD_11),
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.h
index d6d4895371..3bc86f33a5 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1011/periph.h
@@ -27,13 +27,19 @@
 #ifndef MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1011_PERIPH_H
 #define MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1011_PERIPH_H
 
+LPI2C_Type *mcu_i2c_banks[2];
+
 extern const mcu_periph_obj_t mcu_i2c_sda_list[8];
 extern const mcu_periph_obj_t mcu_i2c_scl_list[8];
 
+LPSPI_Type *mcu_spi_banks[2];
+
 extern const mcu_periph_obj_t mcu_spi_sck_list[4];
 extern const mcu_periph_obj_t mcu_spi_mosi_list[4];
 extern const mcu_periph_obj_t mcu_spi_miso_list[4];
 
+LPUART_Type *mcu_uart_banks[4];
+
 extern const mcu_periph_obj_t mcu_uart_rx_list[9];
 extern const mcu_periph_obj_t mcu_uart_tx_list[9];
 extern const mcu_periph_obj_t mcu_uart_rts_list[4];
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.c b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.c
index 60f301668a..814b4120d1 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.c
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.c
@@ -30,7 +30,7 @@
 #include "py/mphal.h"
 #include "mimxrt10xx/periph.h"
 
-LPI2C_Type *mcu_i2c_banks[] = { LPI2C1, LPI2C2, LPI2C3, LPI2C4 };
+LPI2C_Type *mcu_i2c_banks[4] = { LPI2C1, LPI2C2, LPI2C3, LPI2C4 };
 
 const mcu_periph_obj_t mcu_i2c_sda_list[8] = {
     PERIPH_PIN(1, 6, kIOMUXC_LPI2C1_SDA_SELECT_INPUT, 0, &pin_GPIO_EMC_03),
@@ -60,7 +60,7 @@ const mcu_periph_obj_t mcu_i2c_scl_list[8] = {
     PERIPH_PIN(4, 3, kIOMUXC_LPI2C4_SCL_SELECT_INPUT, 1, &pin_GPIO_SD_B1_02),
 };
 
-LPSPI_Type *mcu_spi_banks[] = { LPSPI1, LPSPI2, LPSPI3, LPSPI4 };
+LPSPI_Type *mcu_spi_banks[4] = { LPSPI1, LPSPI2, LPSPI3, LPSPI4 };
 
 const mcu_periph_obj_t mcu_spi_sck_list[8] = {
     PERIPH_PIN(1, 4, kIOMUXC_LPSPI1_SCK_SELECT_INPUT, 0, &pin_GPIO_SD_B0_02),
@@ -104,7 +104,7 @@ const mcu_periph_obj_t mcu_spi_miso_list[8] = {
     PERIPH_PIN(4, 4, kIOMUXC_LPSPI2_SDI_SELECT_INPUT, 1, &pin_GPIO_EMC_35),
 };
 
-LPUART_Type *mcu_uart_banks[] = { LPUART1, LPUART2, LPUART3, LPUART4, LPUART5, LPUART6, LPUART7, LPUART8 };
+LPUART_Type *mcu_uart_banks[8] = { LPUART1, LPUART2, LPUART3, LPUART4, LPUART5, LPUART6, LPUART7, LPUART8 };
 
 const mcu_periph_obj_t mcu_uart_rx_list[16] = {
     PERIPH_PIN(1, 2, 0, 0, &pin_GPIO_AD_B0_07),
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.h
index ba88ef4c61..814bc5f6c3 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1021/periph.h
@@ -28,13 +28,19 @@
 #ifndef MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1021_PERIPH_H
 #define MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1021_PERIPH_H
 
+LPI2C_Type *mcu_i2c_banks[4];
+
 extern const mcu_periph_obj_t mcu_i2c_sda_list[8];
 extern const mcu_periph_obj_t mcu_i2c_scl_list[8];
 
+LPSPI_Type *mcu_spi_banks[4];
+
 extern const mcu_periph_obj_t mcu_spi_sck_list[8];
 extern const mcu_periph_obj_t mcu_spi_mosi_list[8];
 extern const mcu_periph_obj_t mcu_spi_miso_list[8];
 
+LPUART_Type *mcu_uart_banks[8];
+
 extern const mcu_periph_obj_t mcu_uart_rx_list[16];
 extern const mcu_periph_obj_t mcu_uart_tx_list[16];
 extern const mcu_periph_obj_t mcu_uart_rts_list[10];
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.c b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.c
index 9a1a4ab65c..388a1b0147 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.c
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.c
@@ -29,7 +29,7 @@
 #include "py/mphal.h"
 #include "mimxrt10xx/periph.h"
 
-LPI2C_Type *mcu_i2c_banks[] = { LPI2C1, LPI2C2, LPI2C3, LPI2C4 };
+LPI2C_Type *mcu_i2c_banks[4] = { LPI2C1, LPI2C2, LPI2C3, LPI2C4 };
 
 const mcu_periph_obj_t mcu_i2c_sda_list[9] = {
     PERIPH_PIN(1, 2, kIOMUXC_LPI2C1_SDA_SELECT_INPUT, 0, &pin_GPIO_SD_B1_05),
@@ -61,7 +61,7 @@ const mcu_periph_obj_t mcu_i2c_scl_list[9] = {
     PERIPH_PIN(4, 0, kIOMUXC_LPI2C4_SCL_SELECT_INPUT, 1, &pin_GPIO_AD_B0_12),
 };
 
-LPSPI_Type *mcu_spi_banks[] = { LPSPI1, LPSPI2, LPSPI3, LPSPI4 };
+LPSPI_Type *mcu_spi_banks[4] = { LPSPI1, LPSPI2, LPSPI3, LPSPI4 };
 
 const mcu_periph_obj_t mcu_spi_sck_list[8] = {
     PERIPH_PIN(1, 3, kIOMUXC_LPSPI1_SCK_SELECT_INPUT, 0, &pin_GPIO_EMC_27),
@@ -105,7 +105,7 @@ const mcu_periph_obj_t mcu_spi_miso_list[8] = {
     PERIPH_PIN(4, 1, kIOMUXC_LPSPI4_SDI_SELECT_INPUT, 1, &pin_GPIO_B1_05),
 };
 
-LPUART_Type *mcu_uart_banks[] = { LPUART1, LPUART2, LPUART3, LPUART4, LPUART5, LPUART6, LPUART7, LPUART8 };
+LPUART_Type *mcu_uart_banks[8] = { LPUART1, LPUART2, LPUART3, LPUART4, LPUART5, LPUART6, LPUART7, LPUART8 };
 
 const mcu_periph_obj_t mcu_uart_rx_list[18] = {
     PERIPH_PIN(1, 2, 0, 0, &pin_GPIO_AD_B0_13),
diff --git a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.h b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.h
index 45b92f2473..35ac4fc9b7 100644
--- a/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.h
+++ b/ports/mimxrt10xx/peripherals/mimxrt10xx/MIMXRT1062/periph.h
@@ -27,13 +27,19 @@
 #ifndef MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1011_PERIPH_H
 #define MICROPY_INCLUDED_MIMXRT10XX_PERIPHERALS_MIMXRT1011_PERIPH_H
 
+LPI2C_Type *mcu_i2c_banks[4];
+
 extern const mcu_periph_obj_t mcu_i2c_sda_list[9];
 extern const mcu_periph_obj_t mcu_i2c_scl_list[9];
 
+LPSPI_Type *mcu_spi_banks[4];
+
 extern const mcu_periph_obj_t mcu_spi_sck_list[8];
 extern const mcu_periph_obj_t mcu_spi_mosi_list[8];
 extern const mcu_periph_obj_t mcu_spi_miso_list[8];
 
+LPUART_Type *mcu_uart_banks[8];
+
 extern const mcu_periph_obj_t mcu_uart_rx_list[18];
 extern const mcu_periph_obj_t mcu_uart_tx_list[18];
 extern const mcu_periph_obj_t mcu_uart_rts_list[9];
diff --git a/ports/stm/common-hal/busio/SPI.c b/ports/stm/common-hal/busio/SPI.c
index d3310efe06..65eeb8ebcf 100644
--- a/ports/stm/common-hal/busio/SPI.c
+++ b/ports/stm/common-hal/busio/SPI.c
@@ -269,18 +269,14 @@ void common_hal_busio_spi_construct(busio_spi_obj_t *self,
 }
 
 void common_hal_busio_spi_never_reset(busio_spi_obj_t *self) {
-    for (size_t i = 0; i < MP_ARRAY_SIZE(mcu_spi_banks); i++) {
-        if (mcu_spi_banks[i] == self->handle.Instance) {
-            never_reset_spi[i] = true;
-            never_reset_pin_number(self->sck->pin->port, self->sck->pin->number);
-            if (self->mosi != NULL) {
-                never_reset_pin_number(self->mosi->pin->port, self->mosi->pin->number);
-            }
-            if (self->miso != NULL) {
-                never_reset_pin_number(self->miso->pin->port, self->miso->pin->number);
-            }
-            break;
-        }
+
+    never_reset_spi[self->sck->periph_index - 1] = true;
+    never_reset_pin_number(self->sck->pin->port, self->sck->pin->number);
+    if (self->mosi != NULL) {
+        never_reset_pin_number(self->mosi->pin->port, self->mosi->pin->number);
+    }
+    if (self->miso != NULL) {
+        never_reset_pin_number(self->miso->pin->port, self->miso->pin->number);
     }
 }