diff --git a/ports/atmel-samd/boards/arduino_mkr1300/mpconfigboard.h b/ports/atmel-samd/boards/arduino_mkr1300/mpconfigboard.h
index 1deda871a..a508d9191 100644
--- a/ports/atmel-samd/boards/arduino_mkr1300/mpconfigboard.h
+++ b/ports/atmel-samd/boards/arduino_mkr1300/mpconfigboard.h
@@ -7,9 +7,9 @@
 
 #define MICROPY_HW_LED_STATUS   (&pin_PB23)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA09)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA08)
diff --git a/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.h b/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.h
index d98da4d14..02750e646 100644
--- a/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.h
+++ b/ports/atmel-samd/boards/arduino_mkrzero/mpconfigboard.h
@@ -5,9 +5,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA09)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA08)
diff --git a/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h b/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
index 7ab09d447..ec201e6ef 100644
--- a/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
+++ b/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
@@ -10,9 +10,9 @@
 #define MICROPY_PORT_B        (PORT_PB03)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/catwan_usbstick/mpconfigboard.h b/ports/atmel-samd/boards/catwan_usbstick/mpconfigboard.h
index 341dcc27e..7a32bf023 100644
--- a/ports/atmel-samd/boards/catwan_usbstick/mpconfigboard.h
+++ b/ports/atmel-samd/boards/catwan_usbstick/mpconfigboard.h
@@ -7,13 +7,13 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
 #define DEFAULT_SPI_BUS_SCK (&pin_PA19)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA18)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA22)
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define IGNORE_PIN_PA00     1
 #define IGNORE_PIN_PA01     1
diff --git a/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
index 787a3ee55..eb1b90585 100644
--- a/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
@@ -8,9 +8,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA22)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA23)
diff --git a/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
index 2a21b8f02..a16cee0b4 100644
--- a/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
@@ -8,9 +8,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
index a0f79ed72..19a514758 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
@@ -8,9 +8,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
index 85c24bfd0..d3db098e5 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
@@ -8,9 +8,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h b/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
index 59e0b3c61..bc60ba49b 100644
--- a/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
+++ b/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
@@ -12,7 +12,7 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA05)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA04)
@@ -20,7 +20,7 @@
 #define DEFAULT_UART_BUS_RX (&pin_PA05)
 #define DEFAULT_UART_BUS_TX (&pin_PA04)
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define IGNORE_PIN_PA03     1
 #define IGNORE_PIN_PA06     1
diff --git a/ports/atmel-samd/boards/meowmeow/mpconfigboard.h b/ports/atmel-samd/boards/meowmeow/mpconfigboard.h
index fe741a0f7..1304b6dfb 100644
--- a/ports/atmel-samd/boards/meowmeow/mpconfigboard.h
+++ b/ports/atmel-samd/boards/meowmeow/mpconfigboard.h
@@ -10,9 +10,9 @@
 
 // If you change this, then make sure to update the linker scripts as well to
 // make sure you don't overwrite code.
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define CALIBRATE_CRYSTALLESS 1
 
diff --git a/ports/atmel-samd/boards/pewpew10/mpconfigboard.h b/ports/atmel-samd/boards/pewpew10/mpconfigboard.h
index 7dd4a5441..445ccc435 100644
--- a/ports/atmel-samd/boards/pewpew10/mpconfigboard.h
+++ b/ports/atmel-samd/boards/pewpew10/mpconfigboard.h
@@ -5,9 +5,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 
 #define IGNORE_PIN_PB00     1
diff --git a/ports/atmel-samd/boards/pirkey_m0/mpconfigboard.h b/ports/atmel-samd/boards/pirkey_m0/mpconfigboard.h
index a004336bf..288208f65 100644
--- a/ports/atmel-samd/boards/pirkey_m0/mpconfigboard.h
+++ b/ports/atmel-samd/boards/pirkey_m0/mpconfigboard.h
@@ -10,9 +10,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE  0
+#define CIRCUITPY_INTERNAL_NVM_SIZE  256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define IGNORE_PIN_PA02     1
 #define IGNORE_PIN_PA03     1
diff --git a/ports/atmel-samd/boards/samd21x18-bootloader.ld b/ports/atmel-samd/boards/samd21x18-bootloader.ld
index 3eb97ee02..2ef09ba9a 100644
--- a/ports/atmel-samd/boards/samd21x18-bootloader.ld
+++ b/ports/atmel-samd/boards/samd21x18-bootloader.ld
@@ -5,8 +5,9 @@
 /* Specify the memory areas */
 MEMORY
 {
-    /* Leave 8KiB for the bootloader, and 64k for the flash file system. */
-    FLASH (rx) : ORIGIN = 0x00000000 + 8K, LENGTH = 256K - 8K - 64K
+    /* Leave 8KiB for the bootloader, 64k for the flash file system, and 256b
+       for user config. */
+    FLASH (rx) : ORIGIN = 0x00000000 + 8K, LENGTH = 256K - 8K - 64K - 256
     RAM (xrw)  : ORIGIN = 0x20000000, LENGTH = 32K
 }
 
diff --git a/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.h b/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.h
index 3112d3f2a..a50c61cf2 100644
--- a/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.h
+++ b/ports/atmel-samd/boards/sparkfun_samd21_dev/mpconfigboard.h
@@ -5,9 +5,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/sparkfun_samd21_mini/mpconfigboard.h b/ports/atmel-samd/boards/sparkfun_samd21_mini/mpconfigboard.h
index aec54ddfb..6af7fa191 100644
--- a/ports/atmel-samd/boards/sparkfun_samd21_mini/mpconfigboard.h
+++ b/ports/atmel-samd/boards/sparkfun_samd21_mini/mpconfigboard.h
@@ -5,9 +5,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define DEFAULT_I2C_BUS_SCL (&pin_PA23)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA22)
diff --git a/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h b/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
index cef35983e..dd8bc03cc 100644
--- a/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
+++ b/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
@@ -11,9 +11,9 @@
 #define MICROPY_PORT_B        (0)
 #define MICROPY_PORT_C        (0)
 
-#define CIRCUITPY_INTERNAL_NVM_SIZE 0
+#define CIRCUITPY_INTERNAL_NVM_SIZE 256
 
-#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
+#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
 #define IGNORE_PIN_PA03     1
 #define IGNORE_PIN_PA04     1