diff --git a/lib/sdmmc/sdmmc_io.c b/lib/sdmmc/sdmmc_io.c
index 369be8c233..17ab291515 100644
--- a/lib/sdmmc/sdmmc_io.c
+++ b/lib/sdmmc/sdmmc_io.c
@@ -420,7 +420,10 @@ static sdmmc_err_t cis_tuple_func_manfid(const void* p, uint8_t* data, FILE* fp)
     int size = *(data++);
     fprintf(fp, "TUPLE: %s, size: %d\n", tuple->name, size);
     CIS_CHECK_SIZE(size, 4);
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Wcast-align"
     fprintf(fp, "  MANF: %04X, CARD: %04X\n", *(uint16_t*)(data), *(uint16_t*)(data+2));
+    #pragma GCC diagnostic pop
     return SDMMC_OK;
 }
 
@@ -480,7 +483,10 @@ static sdmmc_err_t cis_tuple_func_cftable_entry(const void* p, uint8_t* data, FI
         CIS_CHECK_SIZE(size, 2);
         size-=2;
         CIS_CHECK_UNSUPPORTED(mem_space==1); //other cases not handled yet
+        #pragma GCC diagnostic push
+        #pragma GCC diagnostic ignored "-Wcast-align"
         int len = *(uint16_t*)data;
+        #pragma GCC diagnostic pop
         fprintf(fp, "  LEN: %04X\n", len);
         data+=2;
     }
diff --git a/lib/tinyusb b/lib/tinyusb
index ae73873b5c..3b09b82123 160000
--- a/lib/tinyusb
+++ b/lib/tinyusb
@@ -1 +1 @@
-Subproject commit ae73873b5cba0eb11c89165f4559964940430d44
+Subproject commit 3b09b82123a50bef6b18cf90c2734ae7581da4a3
diff --git a/main.c b/main.c
index e0d99e3143..555e8fafb4 100644
--- a/main.c
+++ b/main.c
@@ -812,9 +812,10 @@ int __attribute__((used)) main(void) {
     // A power brownout here could make it appear as if there's
     // no SPI flash filesystem, and we might erase the existing one.
 
-    // Check whether CIRCUITPY is available. Don't check if it already hasn't been found.
-    if ((safe_mode != NO_CIRCUITPY) && !filesystem_init(safe_mode == NO_SAFE_MODE, false)) {
-        reset_into_safe_mode(NO_CIRCUITPY);
+    // Check whether CIRCUITPY is available. No need to reset to get safe mode
+    // since we haven't run user code yet.
+    if (!filesystem_init(safe_mode == NO_SAFE_MODE, false)) {
+        safe_mode = NO_CIRCUITPY;
     }
 
     // displays init after filesystem, since they could share the flash SPI
diff --git a/ports/broadcom/Makefile b/ports/broadcom/Makefile
index 1179d8fa16..921d26958a 100644
--- a/ports/broadcom/Makefile
+++ b/ports/broadcom/Makefile
@@ -31,7 +31,20 @@ include $(TOP)/supervisor/supervisor.mk
 # Include make rules and variables common across CircuitPython builds.
 include $(TOP)/py/circuitpy_defns.mk
 
-HAL_DIR=hal/$(MCU_SERIES)
+ifeq ($(CHIP_VARIANT), "bcm2711")
+CFLAGS += -mcpu=cortex-a72 -DBCM_VERSION=2711
+CROSS_COMPILE = aarch64-none-elf-
+SUFFIX = 8
+else ifeq ($(CHIP_VARIANT), "bcm2837")
+CFLAGS += -mcpu=cortex-a53 -DBCM_VERSION=2837
+CROSS_COMPILE = aarch64-none-elf-
+SUFFIX = 8
+else ifeq ($(CHIP_VARIANT), "bcm2835")
+CFLAGS += -mcpu=arm1176jzf-s -DBCM_VERSION=2835
+CROSS_COMPILE = arm-none-eabi-
+SUFFIX =
+# TODO add 32-bit support for Cortex-A7 in 2836
+endif
 
 INC += -I. \
 	   -I../.. \
@@ -69,6 +82,7 @@ SRC_C += bindings/videocore/__init__.c \
 		 peripherals/broadcom/mmu.c \
 		 peripherals/broadcom/vcmailbox.c
 
+SRC_S = peripherals/broadcom/boot$(SUFFIX).s
 
 SRC_COMMON_HAL_EXPANDED = $(addprefix shared-bindings/, $(SRC_COMMON_HAL)) \
 						  $(addprefix shared-bindings/, $(SRC_BINDINGS_ENUMS)) \
@@ -82,7 +96,6 @@ SRC_SHARED_MODULE_EXPANDED = $(addprefix shared-bindings/, $(SRC_SHARED_MODULE))
 # because a few modules have files both in common-hal/ and shared-modules/.
 # Doing a $(sort ...) removes duplicates as part of sorting.
 SRC_COMMON_HAL_SHARED_MODULE_EXPANDED = $(sort $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED))
-SRC_S = peripherals/broadcom/boot8.s
 
 OBJ = $(PY_O) $(SUPERVISOR_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_COMMON_HAL_SHARED_MODULE_EXPANDED:.c=.o))
@@ -96,15 +109,6 @@ OBJ += $(addprefix $(BUILD)/, $(SRC_MOD:.c=.o))
 # BCM CLFAGS
 CFLAGS += -ffreestanding -nostartfiles -DMICROPY_HW_MCU_NAME="\"$(CHIP_VARIANT)\""
 
-ifeq ($(CHIP_VARIANT), "bcm2711")
-CFLAGS += -mcpu=cortex-a72 -DBCM_VERSION=2711
-CROSS_COMPILE = aarch64-none-elf-
-else
-CFLAGS += -mcpu=cortex-a53 -DBCM_VERSION=2837
-CROSS_COMPILE = aarch64-none-elf-
-# TODO add 32-bit support for Cortex-A7 and ARM1176
-endif
-
 
 OPTIMIZATION_FLAGS ?= -O3
 CFLAGS += $(OPTIMIZATION_FLAGS)
@@ -134,32 +138,32 @@ CFLAGS += $(INC) -Wall -Werror -std=gnu11 $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT) $
 
 SRC_QSTR += $(SRC_C) $(SRC_SUPERVISOR) $(SRC_COMMON_HAL_EXPANDED) $(SRC_SHARED_MODULE_EXPANDED)
 
-LDFLAGS += $(CFLAGS) -T peripherals/broadcom/link8.ld -Wl,--gc-sections -Wl,-Map=$@.map # -Wl,--cref
+LDFLAGS += $(CFLAGS) -T peripherals/broadcom/link$(SUFFIX).ld -Wl,--gc-sections -Wl,-Map=$@.map # -Wl,--cref
 
 # Use toolchain libm if we're not using our own.
 ifndef INTERNAL_LIBM
 LIBS += -lm
 endif
 
-all: $(BUILD)/firmware.kernel8.img $(BUILD)/firmware.disk.img.zip
+all: $(BUILD)/firmware.kernel$(SUFFIX).img $(BUILD)/firmware.disk.img.zip
 
 %.o: %.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
-$(BUILD)/kernel8.elf: $(OBJ)
+$(BUILD)/kernel$(SUFFIX).elf: $(OBJ)
 	$(STEPECHO) "LINK $@"
 	$(Q)echo $(OBJ) > $(BUILD)/firmware.objs
 	$(Q)$(CC) -o $@ $(LDFLAGS) @$(BUILD)/firmware.objs -Wl,--start-group $(LIBS) -Wl,--end-group
 
-$(BUILD)/kernel8.img: $(BUILD)/kernel8.elf
+$(BUILD)/kernel$(SUFFIX).img: $(BUILD)/kernel$(SUFFIX).elf
 	$(STEPECHO) "Create $@"
-	$(OBJCOPY) -O binary $(BUILD)/kernel8.elf $@
+	$(OBJCOPY) -O binary $(BUILD)/kernel$(SUFFIX).elf $@
 
-$(BUILD)/firmware.kernel8.img: $(BUILD)/kernel8.img
+$(BUILD)/firmware.kernel$(SUFFIX).img: $(BUILD)/kernel$(SUFFIX).img
 	$(STEPECHO) "Create $@"
 	$(CP) $^ $@
 
-$(BUILD)/firmware.disk.img.zip: $(BUILD)/kernel8.img
+$(BUILD)/firmware.disk.img.zip: $(BUILD)/kernel$(SUFFIX).img
 	$(STEPECHO) "Create $@"
 	$(Q)dd if=/dev/zero of=$(BUILD)/circuitpython-disk.img bs=1 count=0 seek=256M
 	$(Q)parted -s $(BUILD)/circuitpython-disk.img mktable msdos
@@ -167,7 +171,7 @@ $(BUILD)/firmware.disk.img.zip: $(BUILD)/kernel8.img
 	$(Q)mkfs.fat -F 32 -n BOOT --offset=2048 $(BUILD)/circuitpython-disk.img
 
 	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M config.txt firmware/bootcode.bin firmware/fixup* firmware/start* firmware/*.dtb ::
-	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M $(BUILD)/kernel8.img ::
+	$(Q)mcopy -i $(BUILD)/circuitpython-disk.img@@1M $(BUILD)/kernel$(SUFFIX).img ::
 	$(Q)zip $@ $(BUILD)/circuitpython-disk.img
 	$(Q)rm $(BUILD)/circuitpython-disk.img
 
diff --git a/ports/broadcom/boards/raspberrypi_zero_w/board.c b/ports/broadcom/boards/raspberrypi_zero_w/board.c
new file mode 100644
index 0000000000..80bea7f8b6
--- /dev/null
+++ b/ports/broadcom/boards/raspberrypi_zero_w/board.c
@@ -0,0 +1,56 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Scott Shawcroft 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
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "supervisor/board.h"
+#include "mpconfigboard.h"
+
+#include "bindings/videocore/Framebuffer.h"
+#include "shared-module/displayio/__init__.h"
+#include "shared-bindings/framebufferio/FramebufferDisplay.h"
+
+void board_init(void) {
+    videocore_framebuffer_obj_t *fb = &allocate_display_bus()->videocore;
+    fb->base.type = &videocore_framebuffer_type;
+    common_hal_videocore_framebuffer_construct(fb, 640, 480);
+
+    framebufferio_framebufferdisplay_obj_t *display = &displays[0].framebuffer_display;
+    display->base.type = &framebufferio_framebufferdisplay_type;
+    common_hal_framebufferio_framebufferdisplay_construct(
+        display,
+        MP_OBJ_FROM_PTR(fb),
+        0,
+        true);
+}
+
+bool board_requests_safe_mode(void) {
+    return false;
+}
+
+void reset_board(void) {
+}
+
+void board_deinit(void) {
+}
diff --git a/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.h b/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.h
new file mode 100644
index 0000000000..389868f882
--- /dev/null
+++ b/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.h
@@ -0,0 +1,6 @@
+#define MICROPY_HW_BOARD_NAME "Raspberry Pi Zero W"
+
+#define DEFAULT_I2C_BUS_SCL         (&pin_GPIO3)
+#define DEFAULT_I2C_BUS_SDA         (&pin_GPIO2)
+
+#define MICROPY_HW_LED_STATUS       (&pin_GPIO47)
diff --git a/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.mk b/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.mk
new file mode 100644
index 0000000000..9e0eb3ba57
--- /dev/null
+++ b/ports/broadcom/boards/raspberrypi_zero_w/mpconfigboard.mk
@@ -0,0 +1,6 @@
+USB_VID = 0x2E8A
+USB_PID = 0xf015
+USB_PRODUCT = "Raspberry Pi Zero"
+USB_MANUFACTURER = "Raspberry Pi"
+
+CHIP_VARIANT = "bcm2835"
diff --git a/ports/broadcom/boards/raspberrypi_zero_w/pins.c b/ports/broadcom/boards/raspberrypi_zero_w/pins.c
new file mode 100644
index 0000000000..bb6632b923
--- /dev/null
+++ b/ports/broadcom/boards/raspberrypi_zero_w/pins.c
@@ -0,0 +1,62 @@
+#include "shared-bindings/board/__init__.h"
+
+#include "shared-module/displayio/__init__.h"
+
+STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
+    CIRCUITPYTHON_BOARD_DICT_STANDARD_ITEMS
+    // These match the names used in Blinka
+    { MP_ROM_QSTR(MP_QSTR_D0), MP_ROM_PTR(&pin_GPIO0) },
+    { MP_ROM_QSTR(MP_QSTR_D1), MP_ROM_PTR(&pin_GPIO1) },
+
+    { MP_ROM_QSTR(MP_QSTR_D2), MP_ROM_PTR(&pin_GPIO2) },
+    { MP_ROM_QSTR(MP_QSTR_SDA), MP_ROM_PTR(&pin_GPIO2) },
+    { MP_ROM_QSTR(MP_QSTR_D3), MP_ROM_PTR(&pin_GPIO3) },
+    { MP_ROM_QSTR(MP_QSTR_SCL), MP_ROM_PTR(&pin_GPIO3) },
+
+    { MP_ROM_QSTR(MP_QSTR_D4), MP_ROM_PTR(&pin_GPIO4) },
+    { MP_ROM_QSTR(MP_QSTR_D5), MP_ROM_PTR(&pin_GPIO5) },
+    { MP_ROM_QSTR(MP_QSTR_D6), MP_ROM_PTR(&pin_GPIO6) },
+
+    { MP_ROM_QSTR(MP_QSTR_D7), MP_ROM_PTR(&pin_GPIO7) },
+    { MP_ROM_QSTR(MP_QSTR_CE1), MP_ROM_PTR(&pin_GPIO7) },
+    { MP_ROM_QSTR(MP_QSTR_D8), MP_ROM_PTR(&pin_GPIO8) },
+    { MP_ROM_QSTR(MP_QSTR_CE0), MP_ROM_PTR(&pin_GPIO8) },
+    { MP_ROM_QSTR(MP_QSTR_D9), MP_ROM_PTR(&pin_GPIO9) },
+    { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_GPIO9) },
+    { MP_ROM_QSTR(MP_QSTR_D10), MP_ROM_PTR(&pin_GPIO10) },
+    { MP_ROM_QSTR(MP_QSTR_MOSI), MP_ROM_PTR(&pin_GPIO10) },
+    { MP_ROM_QSTR(MP_QSTR_D11), MP_ROM_PTR(&pin_GPIO11) },
+    { MP_ROM_QSTR(MP_QSTR_SCLK), MP_ROM_PTR(&pin_GPIO11) },
+    { MP_ROM_QSTR(MP_QSTR_SCK), MP_ROM_PTR(&pin_GPIO11) },
+
+    { MP_ROM_QSTR(MP_QSTR_D12), MP_ROM_PTR(&pin_GPIO12) },
+    { MP_ROM_QSTR(MP_QSTR_D13), MP_ROM_PTR(&pin_GPIO13) },
+
+    { MP_ROM_QSTR(MP_QSTR_D14), MP_ROM_PTR(&pin_GPIO14) },
+    { MP_ROM_QSTR(MP_QSTR_TXD), MP_ROM_PTR(&pin_GPIO14) },
+    { MP_ROM_QSTR(MP_QSTR_D15), MP_ROM_PTR(&pin_GPIO15) },
+    { MP_ROM_QSTR(MP_QSTR_RXD), MP_ROM_PTR(&pin_GPIO15) },
+    { MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_PTR(&pin_GPIO14) },
+    { MP_ROM_QSTR(MP_QSTR_RX), MP_ROM_PTR(&pin_GPIO15) },
+
+    { MP_ROM_QSTR(MP_QSTR_D16), MP_ROM_PTR(&pin_GPIO16) },
+    { MP_ROM_QSTR(MP_QSTR_D17), MP_ROM_PTR(&pin_GPIO17) },
+    { MP_ROM_QSTR(MP_QSTR_D18), MP_ROM_PTR(&pin_GPIO18) },
+    { MP_ROM_QSTR(MP_QSTR_D19), MP_ROM_PTR(&pin_GPIO19) },
+    { MP_ROM_QSTR(MP_QSTR_MISO_1), MP_ROM_PTR(&pin_GPIO19) },
+    { MP_ROM_QSTR(MP_QSTR_D20), MP_ROM_PTR(&pin_GPIO20) },
+    { MP_ROM_QSTR(MP_QSTR_MOSI_1), MP_ROM_PTR(&pin_GPIO20) },
+    { MP_ROM_QSTR(MP_QSTR_D21), MP_ROM_PTR(&pin_GPIO21) },
+    { MP_ROM_QSTR(MP_QSTR_SCLK_1), MP_ROM_PTR(&pin_GPIO21) },
+    { MP_ROM_QSTR(MP_QSTR_SCK_1), MP_ROM_PTR(&pin_GPIO21) },
+    { MP_ROM_QSTR(MP_QSTR_D22), MP_ROM_PTR(&pin_GPIO22) },
+    { MP_ROM_QSTR(MP_QSTR_D23), MP_ROM_PTR(&pin_GPIO23) },
+    { MP_ROM_QSTR(MP_QSTR_D24), MP_ROM_PTR(&pin_GPIO24) },
+    { MP_ROM_QSTR(MP_QSTR_D25), MP_ROM_PTR(&pin_GPIO25) },
+    { MP_ROM_QSTR(MP_QSTR_D26), MP_ROM_PTR(&pin_GPIO26) },
+    { MP_ROM_QSTR(MP_QSTR_D27), MP_ROM_PTR(&pin_GPIO27) },
+
+    { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
+    { MP_ROM_QSTR(MP_QSTR_DISPLAY), MP_ROM_PTR(&displays[0].display)},
+};
+MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/broadcom/common-hal/neopixel_write/__init__.c b/ports/broadcom/common-hal/neopixel_write/__init__.c
index c045317f93..0cd76ebca9 100644
--- a/ports/broadcom/common-hal/neopixel_write/__init__.c
+++ b/ports/broadcom/common-hal/neopixel_write/__init__.c
@@ -48,9 +48,9 @@ void common_hal_neopixel_write(const digitalio_digitalinout_obj_t *digitalinout,
     while (port_get_raw_ticks(NULL) < next_start_raw_ticks) {
     }
 
-    BP_Function_Enum alt_function;
-    uint8_t index;
-    uint8_t channel;
+    BP_Function_Enum alt_function = GPIO_FUNCTION_OUTPUT;
+    uint8_t index = 0;
+    uint8_t channel = 0;
     bool found = false;
     for (size_t i = 0; i < NUM_ALT_FUNC; i++) {
         const pin_function_t *f = &digitalinout->pin->functions[i];
diff --git a/ports/broadcom/common-hal/sdioio/SDCard.c b/ports/broadcom/common-hal/sdioio/SDCard.c
index 492d28d6d6..85a84ac213 100644
--- a/ports/broadcom/common-hal/sdioio/SDCard.c
+++ b/ports/broadcom/common-hal/sdioio/SDCard.c
@@ -37,6 +37,7 @@
 #include "supervisor/port.h"
 #include "supervisor/shared/translate.h"
 
+#include "peripherals/broadcom/cpu.h"
 #include "peripherals/broadcom/defines.h"
 #include "peripherals/broadcom/gpio.h"
 
@@ -235,21 +236,29 @@ void common_hal_sdioio_sdcard_construct(sdioio_sdcard_obj_t *self,
     if (clock != NULL) {
         gpio_set_function(clock->number, GPIO_GPFSEL4_FSEL48_SD1_CLK);
         gpio_set_pull(clock->number, BP_PULL_NONE);
+        self->clock_pin = clock->number;
         gpio_set_function(command->number, GPIO_GPFSEL4_FSEL49_SD1_CMD);
         gpio_set_pull(command->number, BP_PULL_UP);
+        self->command_pin = command->number;
         gpio_set_function(data[0]->number, GPIO_GPFSEL5_FSEL50_SD1_DAT0);
         gpio_set_pull(data[0]->number, BP_PULL_UP);
+        self->data_pins[0] = data[0]->number;
         gpio_set_function(data[1]->number, GPIO_GPFSEL5_FSEL51_SD1_DAT1);
         gpio_set_pull(data[1]->number, BP_PULL_UP);
+        self->data_pins[1] = data[1]->number;
         gpio_set_function(data[2]->number, GPIO_GPFSEL5_FSEL52_SD1_DAT2);
         gpio_set_pull(data[2]->number, BP_PULL_UP);
+        self->data_pins[2] = data[2]->number;
         gpio_set_function(data[3]->number, GPIO_GPFSEL5_FSEL53_SD1_DAT3);
         gpio_set_pull(data[3]->number, BP_PULL_UP);
+        self->data_pins[3] = data[3]->number;
     } else {
         // Switch the sdcard to use the old arasan interface.
         GPIO->EXTRA_MUX_b.SDIO = GPIO_EXTRA_MUX_SDIO_ARASAN;
     }
 
+    COMPLETE_MEMORY_READS;
+
     self->host_info = (sdmmc_host_t) {
         .flags = SDMMC_HOST_FLAG_1BIT | SDMMC_HOST_FLAG_4BIT | SDMMC_HOST_FLAG_DEINIT_ARG,
         .slot = 0,
@@ -280,9 +289,22 @@ void common_hal_sdioio_sdcard_construct(sdioio_sdcard_obj_t *self,
     // Start clocking the card.
     _set_card_clk(0, 400);
 
-    sdmmc_card_init(&self->host_info, &self->card_info);
+    sdmmc_err_t err = SDMMC_ERR_INVALID_RESPONSE;
+    size_t tries = 3;
+    while (err == SDMMC_ERR_INVALID_RESPONSE && tries > 0) {
+        err = sdmmc_card_init(&self->host_info, &self->card_info);
+        if (err != SDMMC_OK) {
+            mp_printf(&mp_plat_print, "SD card init failed %d\n", err);
+        } else if (tries < 3) {
+            mp_printf(&mp_plat_print, "SD card init success\n");
+        }
+        tries--;
+    }
+
+    self->init = err == SDMMC_OK;
 
     self->capacity = self->card_info.csd.capacity;
+    COMPLETE_MEMORY_READS;
 }
 
 uint32_t common_hal_sdioio_sdcard_get_count(sdioio_sdcard_obj_t *self) {
@@ -297,9 +319,6 @@ uint8_t common_hal_sdioio_sdcard_get_width(sdioio_sdcard_obj_t *self) {
     return self->num_data;
 }
 
-STATIC void check_for_deinit(sdioio_sdcard_obj_t *self) {
-}
-
 STATIC void check_whole_block(mp_buffer_info_t *bufinfo) {
     if (bufinfo->len % 512) {
         mp_raise_ValueError(translate("Buffer length must be a multiple of 512"));
@@ -307,14 +326,16 @@ STATIC void check_whole_block(mp_buffer_info_t *bufinfo) {
 }
 
 int common_hal_sdioio_sdcard_writeblocks(sdioio_sdcard_obj_t *self, uint32_t start_block, mp_buffer_info_t *bufinfo) {
-    check_for_deinit(self);
+    if (!self->init) {
+        return -EIO;
+    }
     check_whole_block(bufinfo);
     self->state_programming = true;
 
-    // mp_printf(&mp_plat_print, "write %d %d %d %d\n", start_block, bufinfo->len / 512, self->card_info.csd.capacity, self->card_info.csd.sector_size);
+    COMPLETE_MEMORY_READS;
     sdmmc_err_t error = sdmmc_write_sectors(&self->card_info, bufinfo->buf,
         start_block, bufinfo->len / 512);
-
+    COMPLETE_MEMORY_READS;
 
     if (error != SDMMC_OK) {
         mp_printf(&mp_plat_print, "write sectors result %d\n", error);
@@ -325,10 +346,14 @@ int common_hal_sdioio_sdcard_writeblocks(sdioio_sdcard_obj_t *self, uint32_t sta
 }
 
 int common_hal_sdioio_sdcard_readblocks(sdioio_sdcard_obj_t *self, uint32_t start_block, mp_buffer_info_t *bufinfo) {
-    check_for_deinit(self);
+    if (!self->init) {
+        return -EIO;
+    }
     check_whole_block(bufinfo);
+    COMPLETE_MEMORY_READS;
     sdmmc_err_t error = sdmmc_read_sectors(&self->card_info, bufinfo->buf,
         start_block, bufinfo->len / 512);
+    COMPLETE_MEMORY_READS;
 
     if (error != SDMMC_OK) {
         mp_printf(&mp_plat_print, "read sectors result %d when reading block %d for %d\n", error, start_block, bufinfo->len / 512);
@@ -339,7 +364,9 @@ int common_hal_sdioio_sdcard_readblocks(sdioio_sdcard_obj_t *self, uint32_t star
 }
 
 bool common_hal_sdioio_sdcard_configure(sdioio_sdcard_obj_t *self, uint32_t frequency, uint8_t bits) {
-    check_for_deinit(self);
+    if (!self->init) {
+        return false;
+    }
     return true;
 }
 
@@ -361,7 +388,14 @@ void common_hal_sdioio_sdcard_deinit(sdioio_sdcard_obj_t *self) {
     self->data_pins[1] = COMMON_HAL_MCU_NO_PIN;
     self->data_pins[2] = COMMON_HAL_MCU_NO_PIN;
     self->data_pins[3] = COMMON_HAL_MCU_NO_PIN;
+    self->init = false;
 }
 
 void common_hal_sdioio_sdcard_never_reset(sdioio_sdcard_obj_t *self) {
+    never_reset_pin_number(self->command_pin);
+    never_reset_pin_number(self->clock_pin);
+    never_reset_pin_number(self->data_pins[0]);
+    never_reset_pin_number(self->data_pins[1]);
+    never_reset_pin_number(self->data_pins[2]);
+    never_reset_pin_number(self->data_pins[3]);
 }
diff --git a/ports/broadcom/common-hal/sdioio/SDCard.h b/ports/broadcom/common-hal/sdioio/SDCard.h
index ebd8e13f34..d180bc19a2 100644
--- a/ports/broadcom/common-hal/sdioio/SDCard.h
+++ b/ports/broadcom/common-hal/sdioio/SDCard.h
@@ -37,6 +37,7 @@ typedef struct {
     uint8_t num_data;
     bool state_programming;
     bool has_lock;
+    bool init;
     uint8_t command_pin;
     uint8_t clock_pin;
     uint8_t data_pins[4];
diff --git a/ports/broadcom/common-hal/videocore/Framebuffer.c b/ports/broadcom/common-hal/videocore/Framebuffer.c
index f5f9654949..18b703b8b6 100644
--- a/ports/broadcom/common-hal/videocore/Framebuffer.c
+++ b/ports/broadcom/common-hal/videocore/Framebuffer.c
@@ -16,7 +16,13 @@ void common_hal_videocore_framebuffer_construct(videocore_framebuffer_obj_t *sel
     // TODO: Make the FB twice as tall if double buffering.
     uint32_t physical_height = height;
     uint32_t pitch = 0;
-    self->framebuffer = vcmailbox_get_framebuffer(&virtual_width, &virtual_height, &physical_width, &physical_height, &pitch);
+    uint32_t bits_per_pixel = 0;
+    self->framebuffer = vcmailbox_get_framebuffer(&virtual_width,
+        &virtual_height,
+        &physical_width,
+        &physical_height,
+        &pitch,
+        &bits_per_pixel);
     if (self->framebuffer == NULL) {
         if (gc_alloc_possible()) {
             mp_raise_ValueError(translate("no fb"));
diff --git a/ports/broadcom/mpconfigport.h b/ports/broadcom/mpconfigport.h
index dafe432c3c..abd0580999 100644
--- a/ports/broadcom/mpconfigport.h
+++ b/ports/broadcom/mpconfigport.h
@@ -36,7 +36,11 @@
 #define MICROPY_PY_SYS_PLATFORM                     "BROADCOM"
 #define MICROPY_PY_BUILTINS_NOTIMPLEMENTED          (1)
 #define MICROPY_PY_FUNCTION_ATTRS                   (1)
+#if BCM_VERSION == 2837 || BCM_VERSION == 2711
 #define MICROPY_OBJ_REPR            (MICROPY_OBJ_REPR_A)
+#elif BCM_VERSION == 2835
+#define MICROPY_OBJ_REPR            (MICROPY_OBJ_REPR_C)
+#endif
 #define CIRCUITPY_DEFAULT_STACK_SIZE            (0x10000)
 #define CIRCUITPY_DISPLAY_AREA_BUFFER_SIZE (1920)
 #define CIRCUITPY_PROCESSOR_COUNT (4)
diff --git a/ports/broadcom/mphalport.c b/ports/broadcom/mphalport.c
index 91e7b631bc..fa7dcaac8e 100644
--- a/ports/broadcom/mphalport.c
+++ b/ports/broadcom/mphalport.c
@@ -41,16 +41,16 @@ mp_uint_t cpu_get_regs_and_sp(mp_uint_t *regs) {
     __asm__ ("mov %[out], x28" : [out] "=r" (regs[9]));
     #else
     __asm__ ("mov %[out], sp" : [out] "=r" (sp));
-    __asm__ ("mov %[out], x19" : [out] "=r" (regs[0]));
-    __asm__ ("mov %[out], x20" : [out] "=r" (regs[1]));
-    __asm__ ("mov %[out], x21" : [out] "=r" (regs[2]));
-    __asm__ ("mov %[out], x22" : [out] "=r" (regs[3]));
-    __asm__ ("mov %[out], x23" : [out] "=r" (regs[4]));
-    __asm__ ("mov %[out], x24" : [out] "=r" (regs[5]));
-    __asm__ ("mov %[out], x25" : [out] "=r" (regs[6]));
-    __asm__ ("mov %[out], x26" : [out] "=r" (regs[7]));
-    __asm__ ("mov %[out], x27" : [out] "=r" (regs[8]));
-    __asm__ ("mov %[out], x28" : [out] "=r" (regs[9]));
+    __asm__ ("mov %[out], r4" : [out] "=r" (regs[0]));
+    __asm__ ("mov %[out], r5" : [out] "=r" (regs[1]));
+    __asm__ ("mov %[out], r6" : [out] "=r" (regs[2]));
+    __asm__ ("mov %[out], r7" : [out] "=r" (regs[3]));
+    __asm__ ("mov %[out], r8" : [out] "=r" (regs[4]));
+    __asm__ ("mov %[out], r9" : [out] "=r" (regs[5]));
+    __asm__ ("mov %[out], r10" : [out] "=r" (regs[6]));
+    __asm__ ("mov %[out], r11" : [out] "=r" (regs[7]));
+    __asm__ ("mov %[out], r12" : [out] "=r" (regs[8]));
+    __asm__ ("mov %[out], r13" : [out] "=r" (regs[9]));
     #endif
 
     return sp;
diff --git a/ports/broadcom/peripherals b/ports/broadcom/peripherals
index 2c10889a4b..0837008608 160000
--- a/ports/broadcom/peripherals
+++ b/ports/broadcom/peripherals
@@ -1 +1 @@
-Subproject commit 2c10889a4b2d78987bc4e0783db2e7584aa4d572
+Subproject commit 08370086080759ed54ac1136d62d2ad24c6fa267
diff --git a/ports/broadcom/supervisor/internal_flash.c b/ports/broadcom/supervisor/internal_flash.c
index 08c10848a8..806d3fb18b 100644
--- a/ports/broadcom/supervisor/internal_flash.c
+++ b/ports/broadcom/supervisor/internal_flash.c
@@ -60,6 +60,7 @@ void supervisor_flash_init(void) {
         NULL, NULL,
         0, NULL, 8000000);
     #endif
+    common_hal_sdioio_sdcard_never_reset(&sd);
 
     uint32_t buffer[512 / sizeof(uint32_t)];
     mp_buffer_info_t bufinfo;
diff --git a/ports/broadcom/supervisor/port.c b/ports/broadcom/supervisor/port.c
index 95ad465a84..e036a76cef 100644
--- a/ports/broadcom/supervisor/port.c
+++ b/ports/broadcom/supervisor/port.c
@@ -116,42 +116,57 @@ void reset_to_bootloader(void) {
 }
 
 void reset_cpu(void) {
-
+    // Don't actually reset because we can't store the safe mode info.
+    // PM->WDOG = 1 << PM_WDOG_TIME_Pos | PM_WDOG_PASSWD_PASSWD << PM_WDOG_PASSWD_Pos;
+    // PM->RSTC = PM_RSTC_WRCFG_FULL_RESET << PM_RSTC_WRCFG_Pos | PM_RSTC_PASSWD_PASSWD << PM_RSTC_PASSWD_Pos;
     while (true) {
     }
 }
 
 bool port_has_fixed_stack(void) {
+    #ifdef __aarch64__
     return true;
-}
-
-uint32_t *port_stack_get_limit(void) {
-    return (uint32_t *)0x4;
-}
-
-uint32_t *port_stack_get_top(void) {
-    return (uint32_t *)0x80000;
+    #else
+    return false;
+    #endif
 }
 
 // From the linker script
 extern uint32_t __bss_end;
+extern uint32_t _ld_ram_end;
+uint32_t *port_stack_get_limit(void) {
+    #ifdef __aarch64__
+    return (uint32_t *)0x4;
+    #else
+    return &__bss_end;
+    #endif
+}
+
+uint32_t *port_stack_get_top(void) {
+    #ifdef __aarch64__
+    return (uint32_t *)0x80000;
+    #else
+    return &_ld_ram_end;
+    #endif
+}
+
 uint32_t *port_heap_get_bottom(void) {
     return &__bss_end;
 }
 
 uint32_t *port_heap_get_top(void) {
     // 32M heap
-    return (uint32_t *)(((uint64_t)&__bss_end) + 32 * 1024 * 1024);
+    return (uint32_t *)(((size_t)&__bss_end) + 32 * 1024 * 1024);
 }
 
 void port_set_saved_word(uint32_t value) {
     // NOTE: This doesn't survive pressing the reset button (aka toggling RUN).
-    // watchdog_hw->scratch[0] = value;
+    __bss_end = value;
+    data_clean_and_invalidate(&__bss_end, sizeof(uint32_t));
 }
 
 uint32_t port_get_saved_word(void) {
-    // return watchdog_hw->scratch[0];
-    return 0;
+    return __bss_end;
 }
 
 uint64_t port_get_raw_ticks(uint8_t *subticks) {
diff --git a/ports/mimxrt10xx/Makefile b/ports/mimxrt10xx/Makefile
index dd691a12e9..0ac74579a7 100644
--- a/ports/mimxrt10xx/Makefile
+++ b/ports/mimxrt10xx/Makefile
@@ -156,7 +156,7 @@ SRC_C += \
 	boards/$(BOARD)/flash_config.c \
 	boards/$(BOARD)/pins.c \
 	fatfs_port.c \
-	lib/tinyusb/src/portable/nxp/transdimension/dcd_transdimension.c \
+	lib/tinyusb/src/portable/chipidea/ci_hs/dcd_ci_hs.c \
 	mphalport.c \
 	peripherals/mimxrt10xx/$(CHIP_FAMILY)/clocks.c \
 	peripherals/mimxrt10xx/$(CHIP_FAMILY)/periph.c \
diff --git a/tools/build_board_info.py b/tools/build_board_info.py
index 3ebd799b11..ca080ac9cc 100644
--- a/tools/build_board_info.py
+++ b/tools/build_board_info.py
@@ -32,6 +32,7 @@ DFU = ("dfu",)
 BIN_DFU = ("bin", "dfu")
 COMBINED_HEX = ("combined.hex",)
 KERNEL8_IMG = ("disk.img.zip", "kernel8.img")
+KERNEL_IMG = ("disk.img.zip", "kernel.img")
 
 # Default extensions
 extension_by_port = {
@@ -70,6 +71,8 @@ extension_by_board = {
     # esp32c3
     "ai_thinker_esp32-c3s": BIN,
     "microdev_micro_c3": BIN,
+    # broadcom
+    "raspberrypi_zero_w": KERNEL_IMG,
 }
 
 language_allow_list = set(