diff --git a/ports/nrf/mpconfigport.h b/ports/nrf/mpconfigport.h
index 00ec956d13..e357f01caf 100644
--- a/ports/nrf/mpconfigport.h
+++ b/ports/nrf/mpconfigport.h
@@ -63,6 +63,7 @@
 #define MICROPY_VFS                        (CORE_FEAT)
 #endif
 
+// micro:bit filesystem
 #ifndef MICROPY_MBFS
 #define MICROPY_MBFS                       (!MICROPY_VFS)
 #endif
@@ -101,15 +102,12 @@
 
 #define MICROPY_ALLOC_PATH_MAX      (512)
 #define MICROPY_PERSISTENT_CODE_LOAD (1)
-#define MICROPY_COMP_MODULE_CONST   (0)
-#define MICROPY_COMP_TRIPLE_TUPLE_ASSIGN (0)
 #define MICROPY_READER_VFS          (MICROPY_VFS)
 #define MICROPY_ENABLE_GC           (1)
 #define MICROPY_ENABLE_FINALISER    (1)
 #define MICROPY_STACK_CHECK         (1)
 #define MICROPY_HELPER_REPL         (1)
 #define MICROPY_REPL_INFO           (1)
-#define MICROPY_REPL_EMACS_KEYS     (0)
 #define MICROPY_REPL_AUTO_INDENT    (1)
 #define MICROPY_KBD_EXCEPTION       (1)
 #define MICROPY_LONGINT_IMPL        (MICROPY_LONGINT_IMPL_MPZ)
@@ -122,9 +120,6 @@
 #define MICROPY_ALLOC_GC_STACK_SIZE (32)
 #endif
 
-#define MICROPY_OPT_COMPUTED_GOTO   (0)
-#define MICROPY_OPT_MPZ_BITWISE     (0)
-
 // fatfs configuration used in ffconf.h
 #define MICROPY_FATFS_ENABLE_LFN       (1)
 #define MICROPY_FATFS_LFN_CODE_PAGE    437 /* 1=SFN/ANSI 437=LFN/U.S.(OEM) */
@@ -142,10 +137,8 @@
 #define mp_type_fileio fatfs_type_fileio
 #define mp_type_textio fatfs_type_textio
 
-// Enable micro:bit filesystem by default.
-#ifndef MICROPY_MBFS
-#define MICROPY_MBFS (1)
-#endif
+// Use port specific uos module rather than extmod variant.
+#define MICROPY_PY_UOS              (0)
 
 #define MICROPY_STREAMS_NON_BLOCK   (1)
 #define MICROPY_MODULE_WEAK_LINKS   (1)
@@ -153,42 +146,24 @@
 #define MICROPY_USE_INTERNAL_ERRNO  (1)
 #define MICROPY_PY_FUNCTION_ATTRS   (1)
 #define MICROPY_PY_BUILTINS_STR_UNICODE (1)
-#define MICROPY_PY_BUILTINS_STR_CENTER (0)
-#define MICROPY_PY_BUILTINS_STR_PARTITION (0)
-#define MICROPY_PY_BUILTINS_STR_SPLITLINES (0)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (1)
 #define MICROPY_PY_BUILTINS_FROZENSET (1)
-#define MICROPY_PY_BUILTINS_EXECFILE (0)
 #define MICROPY_PY_BUILTINS_COMPILE (1)
 #define MICROPY_PY_BUILTINS_HELP    (1)
 #define MICROPY_PY_BUILTINS_HELP_TEXT nrf5_help_text
 #define MICROPY_PY_BUILTINS_HELP_MODULES (1)
 #define MICROPY_MODULE_BUILTIN_INIT (1)
-#define MICROPY_PY_ALL_SPECIAL_METHODS (0)
 #define MICROPY_PY_MICROPYTHON_MEM_INFO (1)
-#define MICROPY_PY_BUILTINS_SLICE_ATTRS (0)
-#define MICROPY_PY_SYS_EXIT         (1)
 #define MICROPY_PY_SYS_MAXSIZE      (1)
-#define MICROPY_PY_SYS_STDIO_BUFFER (0)
-#define MICROPY_PY_COLLECTIONS_ORDEREDDICT (0)
-#define MICROPY_PY_MATH_SPECIAL_FUNCTIONS (0)
-#define MICROPY_PY_CMATH            (0)
-#define MICROPY_PY_IO               (0)
 #define MICROPY_PY_IO_FILEIO        (MICROPY_VFS_FAT || MICROPY_VFS_LFS1 || MICROPY_VFS_LFS2)
 #define MICROPY_PY_URANDOM          (1)
 #define MICROPY_PY_URANDOM_EXTRA_FUNCS (1)
-#define MICROPY_PY_UCTYPES          (0)
-#define MICROPY_PY_UZLIB            (0)
-#define MICROPY_PY_UJSON            (0)
-#define MICROPY_PY_URE              (0)
-#define MICROPY_PY_UHEAPQ           (0)
 #define MICROPY_PY_UTIME_MP_HAL     (1)
 #define MICROPY_PY_MACHINE          (1)
 #define MICROPY_PY_MACHINE_PULSE    (0)
 #define MICROPY_PY_MACHINE_SOFTI2C  (MICROPY_PY_MACHINE_I2C)
 #define MICROPY_PY_MACHINE_SPI      (0)
 #define MICROPY_PY_MACHINE_SPI_MIN_DELAY (0)
-#define MICROPY_PY_FRAMEBUF         (0)
 
 #ifndef MICROPY_HW_LED_COUNT
 #define MICROPY_HW_LED_COUNT        (0)
@@ -324,7 +299,6 @@ extern const struct _mp_obj_module_t music_module;
 #define MICROPY_PORT_CONSTANTS \
     { MP_ROM_QSTR(MP_QSTR_board), MP_ROM_PTR(&board_module) }, \
     { MP_ROM_QSTR(MP_QSTR_machine), MP_ROM_PTR(&mp_module_machine) }, \
-    BLE_MODULE \
 
 #define MP_STATE_PORT MP_STATE_VM
 
@@ -379,38 +353,3 @@ extern const struct _mp_obj_module_t music_module;
 #ifndef MP_NEED_LOG2
 #define MP_NEED_LOG2                (1)
 #endif
-
-// Disable extra features enabled by EXTRA on NRF52840 & NRF9160
-// to initially preserve existing feature set
-#if (EXTRA_FEAT)
-#define MICROPY_COMP_RETURN_IF_EXPR (0)
-#define MICROPY_ENABLE_SCHEDULER (0)
-#define MICROPY_MODULE_ATTR_DELEGATION (0)
-#define MICROPY_OPT_LOAD_ATTR_FAST_PATH (0)
-#define MICROPY_OPT_MAP_LOOKUP_CACHE (0)
-#define MICROPY_OPT_MATH_FACTORIAL (0)
-#define MICROPY_PY_BUILTINS_INPUT (0)
-#define MICROPY_PY_BUILTINS_NOTIMPLEMENTED (0)
-#define MICROPY_PY_BUILTINS_POW3 (0)
-#define MICROPY_PY_BUILTINS_ROUND_INT (0)
-#define MICROPY_PY_BUILTINS_SLICE_INDICES (0)
-#define MICROPY_PY_COLLECTIONS_DEQUE (0)
-#define MICROPY_PY_DELATTR_SETATTR (0)
-#define MICROPY_PY_DESCRIPTORS (0)
-#define MICROPY_PY_FSTRINGS (0)
-#define MICROPY_PY_IO_IOBASE (0)
-#define MICROPY_PY_MATH_CONSTANTS (0)
-#define MICROPY_PY_MATH_FACTORIAL (0)
-#define MICROPY_PY_MATH_ISCLOSE (0)
-#define MICROPY_PY_REVERSE_SPECIAL_METHODS (0)
-#define MICROPY_PY_SYS_ATTR_DELEGATION (0)
-#define MICROPY_PY_SYS_PS1_PS2 (0)
-#define MICROPY_PY_UASYNCIO (0)
-#define MICROPY_PY_UBINASCII_CRC32 (0)
-#define MICROPY_PY_UERRNO (0)
-#define MICROPY_PY_UHASHLIB (0)
-#define MICROPY_PY_UOS (0)
-#define MICROPY_PY_UOS_STATVFS (0)
-#define MICROPY_PY_URE_SUB (0)
-#define MICROPY_PY_USELECT (0)
-#endif