feat(core): add prepare build for STM32U

5, which sets option bytes so that boardloader starts correctly

[no changelog]

core/Makefile

@@ -11,6 +11,7 @@ MAKE = make -j $(JOBS)
 SCONS = scons -Q -j $(JOBS)
 
 BUILD_DIR             = build
+PREPARE_BUILD_DIR = $(BUILD_DIR)/prepare
 BOARDLOADER_BUILD_DIR = $(BUILD_DIR)/boardloader
 BOOTLOADER_BUILD_DIR  = $(BUILD_DIR)/bootloader
 BOOTLOADER_CI_BUILD_DIR   = $(BUILD_DIR)/bootloader_ci
@@ -229,6 +230,10 @@ build: build_boardloader build_bootloader build_firmware build_prodtest build_un
 
 build_embed: build_boardloader build_bootloader build_firmware # build boardloader, bootloader, firmware
 
+build_prepare: ## build prepare
+	$(SCONS) CFLAGS="$(CFLAGS)" PRODUCTION="$(PRODUCTION)" TREZOR_MODEL="$(TREZOR_MODEL)" \
+		CMAKELISTS="$(CMAKELISTS)" $(PREPARE_BUILD_DIR)/prepare.bin
+
 build_boardloader: ## build boardloader
 	$(SCONS) CFLAGS="$(CFLAGS)" PRODUCTION="$(PRODUCTION)" TREZOR_MODEL="$(TREZOR_MODEL)" \
 		CMAKELISTS="$(CMAKELISTS)" $(BOARDLOADER_BUILD_DIR)/boardloader.bin
@@ -283,9 +288,12 @@ build_cross: ## build mpy-cross port
 
 ## clean commands:
 
-clean: clean_boardloader clean_bootloader clean_bootloader_emu clean_bootloader_ci clean_prodtest clean_reflash clean_firmware clean_unix clean_cross ## clean all
+clean: clean_prepare clean_boardloader clean_bootloader clean_bootloader_emu clean_bootloader_ci clean_prodtest clean_reflash clean_firmware clean_unix clean_cross ## clean all
 	rm -f ".sconsign.dblite"
 
+clean_prepare: ## clean prepare build
+	rm -rf $(PREPARE_BUILD_DIR)
+
 clean_boardloader: ## clean boardloader build
 	rm -rf $(BOARDLOADER_BUILD_DIR)
 
@@ -317,6 +325,9 @@ clean_cross: ## clean mpy-cross build
 
 flash: flash_boardloader flash_bootloader flash_firmware ## flash everything using OpenOCD
 
+flash_prepare: $(PREPARE_BUILD_DIR)/prepare.bin ## flash prepare using OpenOCD
+	$(OPENOCD) -c "init; reset halt; flash write_image erase $< $(FLASH_START); exit"
+
 flash_boardloader: $(BOARDLOADER_BUILD_DIR)/boardloader.bin ## flash boardloader using OpenOCD
 	$(OPENOCD) -c "init; reset halt; flash write_image erase $< $(BOARDLOADER_START); exit"
 
@@ -416,6 +427,8 @@ sizecheck: ## check sizes of binary files
 	test $(FIRMWARE_P2_MAXSIZE) -ge $(shell wc -c < $(FIRMWARE_BUILD_DIR)/firmware.bin.p2)
 	test $(FIRMWARE_MAXSIZE) -ge $(shell wc -c < $(FIRMWARE_BUILD_DIR)/firmware.bin)
 
+
+ifeq  ($(MCU),$(filter $(MCU),STM32F4))
 combine: ## combine boardloader + bootloader + prodtest into one combined image
 	./tools/combine_firmware \
 		$(LAYOUT_FILE) \
@@ -423,8 +436,6 @@ combine: ## combine boardloader + bootloader + prodtest into one combined image
 		-b BOARDLOADER $(BOARDLOADER_BUILD_DIR)/boardloader.bin \
 		-b BOOTLOADER $(BOOTLOADER_BUILD_DIR)/bootloader.bin \
 		-b FIRMWARE $(PRODTEST_BUILD_DIR)/prodtest.bin
-
-ifeq  ($(MCU),$(filter $(MCU),STM32F4))
 combine_fw: ## combine boardloader + bootloader + firmware into one combined image
 	./tools/combine_firmware \
 		$(LAYOUT_FILE) \
@@ -434,10 +445,19 @@ combine_fw: ## combine boardloader + bootloader + firmware into one combined ima
 		-b FIRMWARE $(FIRMWARE_BUILD_DIR)/firmware.bin.p1 \
 		-b FIRMWARE_P2 $(FIRMWARE_BUILD_DIR)/firmware.bin.p2
 else ifeq ($(MCU),$(filter $(MCU),STM32U5))
+combine: ## combine boardloader + bootloader + prodtest into one combined image
+	./tools/combine_firmware \
+		$(LAYOUT_FILE) \
+		$(PRODTEST_BUILD_DIR)/combined.bin \
+		-b FLASH $(PREPARE_BUILD_DIR)/prepare.bin \
+		-b BOARDLOADER $(BOARDLOADER_BUILD_DIR)/boardloader.bin \
+		-b BOOTLOADER $(BOOTLOADER_BUILD_DIR)/bootloader.bin \
+		-b FIRMWARE $(PRODTEST_BUILD_DIR)/prodtest.bin
 combine_fw: ## combine boardloader + bootloader + firmware into one combined image
 	./tools/combine_firmware \
 		$(LAYOUT_FILE) \
 		$(PRODTEST_BUILD_DIR)/combined.bin \
+		-b FLASH $(PREPARE_BUILD_DIR)/prepare.bin \
 		-b BOARDLOADER $(BOARDLOADER_BUILD_DIR)/boardloader.bin \
 		-b BOOTLOADER $(BOOTLOADER_BUILD_DIR)/bootloader.bin \
 		-b FIRMWARE $(FIRMWARE_BUILD_DIR)/firmware.bin

core/SConscript.prepare

@@ -0,0 +1,144 @@
+# pylint: disable=E0602
+
+import os
+import tools
+
+TREZOR_MODEL = ARGUMENTS.get('TREZOR_MODEL', 'T')
+CMAKELISTS = int(ARGUMENTS.get('CMAKELISTS', 0))
+
+if TREZOR_MODEL not in ('T3T1', ):
+    # skip prepare build
+    env = Environment()
+    def build_prepare(target,source,env):
+        print(f'Prepare: nothing to build for Model {TREZOR_MODEL}')
+    program_bin = env.Command(
+                 target='prepare.bin',
+                 source=None,
+                 action=build_prepare
+             )
+    Return()
+
+FEATURES_WANTED = []
+
+CCFLAGS_MOD = ''
+CPPPATH_MOD = []
+CPPDEFINES_MOD = ["PREPARE"]
+SOURCE_MOD = []
+CPPDEFINES_HAL = []
+SOURCE_HAL = []
+PATH_HAL = []
+
+CPPPATH_MOD += [
+    'vendor/trezor-crypto',
+    'vendor/trezor-storage',
+]
+
+CCFLAGS_MOD += '-Wno-sequence-point '
+
+
+env = Environment(ENV=os.environ,
+     CFLAGS='%s -DPRODUCTION=%s' % (ARGUMENTS.get('CFLAGS', ''), ARGUMENTS.get('PRODUCTION', '0')),
+     CONSTRAINTS=[],
+     CPPDEFINES_IMPLICIT=[]
+ )
+
+FEATURES_AVAILABLE = tools.configure_board(TREZOR_MODEL, FEATURES_WANTED, env, CPPDEFINES_HAL, SOURCE_HAL, PATH_HAL)
+
+FILE_SUFFIX= env.get('ENV')['SUFFIX']
+LINKER_SCRIPT_SUFFIX= env.get('ENV')['LINKER_SCRIPT']
+
+SOURCE_PREPARE = [
+    f"embed/prepare/startup_{FILE_SUFFIX}.s",
+    'embed/prepare/main.c',
+    'embed/lib/terminal.c',
+    'embed/lib/fonts/font_bitmap.c',
+    'embed/lib/mini_printf.c',
+]
+
+env.Replace(
+    CP='cp',
+    AS='arm-none-eabi-as',
+    AR='arm-none-eabi-ar',
+    CC='arm-none-eabi-gcc',
+    LINK='arm-none-eabi-gcc',
+    SIZE='arm-none-eabi-size',
+    STRIP='arm-none-eabi-strip',
+    OBJCOPY='arm-none-eabi-objcopy',
+    PYTHON='python',
+    MAKECMAKELISTS='$PYTHON tools/make_cmakelists.py',)
+
+env.Replace(
+    TREZOR_MODEL=TREZOR_MODEL, )
+
+env.Replace(
+    COPT=env.get('ENV').get('OPTIMIZE', '-Os'),
+    CCFLAGS='$COPT '
+    '-g3 '
+    '-nostdlib '
+    '-std=gnu11 -Wall -Werror -Wdouble-promotion -Wpointer-arith -Wno-missing-braces -fno-common '
+    '-fsingle-precision-constant -fdata-sections -ffunction-sections '
+    '-ffreestanding '
+    '-fstack-protector-all '
+    + env.get('ENV')["CPU_CCFLAGS"] + CCFLAGS_MOD,
+    CCFLAGS_QSTR='-DNO_QSTR -DN_X64 -DN_X86 -DN_THUMB',
+    LINKFLAGS=f"-T embed/prepare/memory_{LINKER_SCRIPT_SUFFIX}.ld -Wl,--gc-sections -Wl,-Map=build/prepare/prepare.map -Wl,--warn-common  -Wl,--print-memory-usage",
+    CPPPATH=[
+        'embed/prepare',
+        'embed/lib',
+        'embed/models',
+        'embed/trezorhal',
+        'embed/extmod/modtrezorui',
+        'vendor/micropython/lib/cmsis/inc',
+    ] + CPPPATH_MOD + PATH_HAL,
+    CPPDEFINES=[
+        'PREPARE',
+        'TREZOR_MODEL_'+TREZOR_MODEL,
+        'USE_HAL_DRIVER',
+    ] + CPPDEFINES_MOD + CPPDEFINES_HAL,
+    ASFLAGS=env.get('ENV')['CPU_ASFLAGS'],
+    ASPPFLAGS='$CFLAGS $CCFLAGS',
+    )
+
+env.Replace(
+    ALLSOURCES=SOURCE_MOD + SOURCE_PREPARE + SOURCE_HAL,
+    ALLDEFS=tools.get_defs_for_cmake(env['CPPDEFINES'] + env['CPPDEFINES_IMPLICIT']))
+
+cmake_gen = env.Command(
+    target='CMakeLists.txt',
+    source='',
+    action='$MAKECMAKELISTS --sources $ALLSOURCES --dirs $CPPPATH --defs $ALLDEFS',
+)
+
+#
+# Program objects
+#
+
+obj_program = []
+obj_program += env.Object(source=SOURCE_MOD)
+obj_program += env.Object(source=SOURCE_PREPARE)
+obj_program += env.Object(source=SOURCE_HAL)
+
+program_elf = env.Command(
+    target='prepare.elf',
+    source=obj_program,
+    action=
+    '$LINK -o $TARGET $CCFLAGS $CFLAGS $LINKFLAGS $SOURCES -lc_nano -lgcc',
+)
+
+BINARY_NAME = f"build/prepare/prepare-{tools.get_model_identifier(TREZOR_MODEL)}"
+BINARY_NAME += "-" + tools.get_version('embed/prepare/version.h')
+BINARY_NAME += "-" + tools.get_git_revision_short_hash()
+BINARY_NAME += "-dirty" if tools.get_git_modified() else ""
+BINARY_NAME += ".bin"
+
+if CMAKELISTS != 0:
+    env.Depends(program_elf, cmake_gen)
+
+program_bin = env.Command(
+    target='prepare.bin',
+    source=program_elf,
+    action=[
+        '$OBJCOPY -O binary -j .vector_table -j .text -j .data -j .rodata -j .capabilities -j .sensitive $SOURCE $TARGET',
+        '$CP $TARGET ' + BINARY_NAME,
+    ],
+)

core/SConstruct

@@ -9,5 +9,6 @@ SConscript('SConscript.bootloader_ci', variant_dir='build/bootloader_ci', duplic
 SConscript('SConscript.bootloader_emu', variant_dir='build/bootloader_emu', duplicate=False)
 SConscript('SConscript.firmware', variant_dir='build/firmware', duplicate=False)
 SConscript('SConscript.prodtest', variant_dir='build/prodtest', duplicate=False)
+SConscript('SConscript.prepare', variant_dir='build/prepare', duplicate=False)
 SConscript('SConscript.reflash', variant_dir='build/reflash', duplicate=False)
 SConscript('SConscript.unix', variant_dir='build/unix', duplicate=False)

core/embed/prepare/main.c

@@ -0,0 +1,34 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include TREZOR_BOARD
+#include "lowlevel.h"
+
+int main(void) {
+  // need the systick timer running before many HAL operations.
+  // want the PVD enabled before flash operations too.
+  periph_init();
+
+  if (sectrue != flash_configure_basic_option_bytes()) {
+    NVIC_SystemReset();
+    return 2;
+  }
+
+  return 0;
+}

core/embed/prepare/memory_stm32u58.ld

@@ -0,0 +1,109 @@
+/* Trezor v2 boardloader linker script */
+
+ENTRY(reset_handler)
+
+MEMORY {
+  FLASH  (rx)  : ORIGIN = 0x0C000000, LENGTH = 16K
+  SRAM1  (wal) : ORIGIN = 0x30000000, LENGTH =  192K - 0x100
+  BOOT_ARGS  (wal) : ORIGIN = 0x3002FF00, LENGTH =  0x100
+  SRAM2  (wal) : ORIGIN = 0x30030000, LENGTH =  64K
+  SRAM3  (wal) : ORIGIN = 0x30040000, LENGTH =  512K
+  SRAM5  (wal) : ORIGIN = 0x30080000, LENGTH =  0K  /* SRAM5 is not available */
+  SRAM6  (wal) : ORIGIN = 0x30080000, LENGTH =  0K  /* SRAM6 is not available */
+  SRAM4  (wal) : ORIGIN = 0x38000000, LENGTH =  16K
+}
+
+main_stack_base = ORIGIN(SRAM2) + SIZEOF(.stack); /* 8-byte aligned full descending stack */
+_sstack = ORIGIN(SRAM2);
+_estack = main_stack_base;
+
+/* used by the startup code to populate variables used by the C code */
+data_lma = LOADADDR(.data);
+data_vma = ADDR(.data);
+data_size = SIZEOF(.data);
+
+/* used by the startup code to populate variables used by the C code */
+sensitive_lma = LOADADDR(.sensitive);
+sensitive_vma = ADDR(.sensitive);
+sensitive_size = SIZEOF(.sensitive);
+
+/* used by the startup code to wipe memory */
+sram1_start = ORIGIN(SRAM1);
+sram1_end = ORIGIN(SRAM1) + LENGTH(SRAM1);
+sram2_start = ORIGIN(SRAM2);
+sram2_end = ORIGIN(SRAM2) + LENGTH(SRAM2);
+sram3_start = ORIGIN(SRAM3);
+sram3_end = ORIGIN(SRAM3) + LENGTH(SRAM3);
+sram4_start = ORIGIN(SRAM4);
+sram4_end = ORIGIN(SRAM4) + LENGTH(SRAM4);
+sram5_start = ORIGIN(SRAM5);
+sram5_end = ORIGIN(SRAM5) + LENGTH(SRAM5);
+sram6_start = ORIGIN(SRAM6);
+sram6_end = ORIGIN(SRAM6) + LENGTH(SRAM6);
+
+/* reserve 256 bytes for bootloader arguments */
+boot_args_start = ORIGIN(BOOT_ARGS);
+boot_args_end = ORIGIN(BOOT_ARGS) + LENGTH(BOOT_ARGS);
+
+SECTIONS {
+  .vector_table : ALIGN(512) {
+    KEEP(*(.vector_table));
+  } >FLASH AT>FLASH
+
+  .text : ALIGN(4) {
+    *(.text*);
+    . = ALIGN(4); /* make the section size a multiple of the word size */
+  } >FLASH AT>FLASH
+
+  .rodata : ALIGN(4) {
+    *(.rodata*);
+    . = ALIGN(4); /* make the section size a multiple of the word size */
+  } >FLASH AT>FLASH
+
+  .data : ALIGN(4) {
+    *(.data*);
+    . = ALIGN(8);
+  } >SRAM1 AT>FLASH
+
+  /DISCARD/ : {
+    *(.ARM.exidx*);
+  }
+
+  .bss : ALIGN(4) {
+    *(.bss*);
+    . = ALIGN(4);
+  } >SRAM1
+
+  .buf : ALIGN(4) {
+    *(.buf*);
+    . = ALIGN(4);
+  } >SRAM1
+
+  .stack : ALIGN(8) {
+    . = 16K; /* Overflow causes UsageFault */
+  } >SRAM2
+
+  .sensitive : ALIGN(8) {
+    *(.sensitive*);
+    . = ALIGN(4);
+  } >SRAM2 AT>FLASH
+
+  .fb : ALIGN(4) {
+   __fb_start = .;
+    *(.fb1*);
+    *(.fb2*);
+   __fb_end = .;
+    . = ALIGN(4);
+  } >SRAM3
+
+  .boot_args : ALIGN(8) {
+    *(.boot_command*);
+    . = ALIGN(8);
+    *(.boot_args*);
+    . = ALIGN(8);
+  } >BOOT_ARGS
+
+
+  /* Hard-coded address for capabilities structure */
+  .capabilities 0x0C00FF00 : {KEEP(*(.capabilities_section))}
+}

core/embed/prepare/startup_stm32u5.s

@@ -0,0 +1,107 @@
+  .syntax unified
+
+  .text
+
+  .global reset_handler
+  .type reset_handler, STT_FUNC
+reset_handler:
+  // set the stack protection
+  ldr r0, =_sstack
+  add r0, r0, #16        // padding
+  msr MSPLIM, r0
+
+  bl SystemInit
+
+  // read the first rng data and save it
+  ldr r0, =0            // r0 - previous value
+  ldr r1, =0            // r1 - whether to compare the previous value
+  bl rng_read
+
+  // read the next rng data and make sure it is different than previous
+  // r0 - value returned from previous call
+  ldr r1, =1            // r1 - whether to compare the previous value
+  bl rng_read
+  mov r4, r0            // save TRNG output in r4
+
+  // wipe memory to remove any possible vestiges of sensitive data
+
+
+fill_ram:
+  ldr r0, =sram1_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram1_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+  ldr r0, =sram2_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram2_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+  ldr r0, =sram3_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram3_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+  ldr r0, =sram4_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram4_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+  ldr r0, =sram5_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram5_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+  ldr r0, =sram6_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram6_end     // r1 - point to byte after the end of SRAM
+  mov r2, r4             // r2 - the word-sized value to be written
+  bl memset_reg
+
+
+  // setup environment for subsequent stage of code
+
+
+clear_ram:
+  ldr r2, =0             // r2 - the word-sized value to be written
+  ldr r0, =sram1_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram1_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+  ldr r0, =sram2_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram2_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+  ldr r0, =sram3_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram3_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+  ldr r0, =sram4_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram4_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+  ldr r0, =sram5_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram5_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+  ldr r0, =sram6_start   // r0 - point to beginning of SRAM
+  ldr r1, =sram6_end     // r1 - point to byte after the end of SRAM
+  bl memset_reg
+
+  // copy data in from flash
+  ldr r0, =data_vma     // dst addr
+  ldr r1, =data_lma     // src addr
+  ldr r2, =data_size    // size in bytes
+  bl memcpy
+
+  // copy sensitive data in from flash
+  ldr r0, =sensitive_vma     // dst addr
+  ldr r1, =sensitive_lma     // src addr
+  ldr r2, =sensitive_size    // size in bytes
+  bl memcpy
+
+  // setup the stack protector (see build script "-fstack-protector-all") with an unpredictable value
+  bl rng_get
+  ldr r1, = __stack_chk_guard
+  str r0, [r1]
+
+  // enter the application code
+  bl main
+
+  b shutdown_privileged
+
+  .end

core/embed/prepare/version.h

@@ -0,0 +1,4 @@
+#define VERSION_MAJOR 0
+#define VERSION_MINOR 0
+#define VERSION_PATCH 1
+#define VERSION_BUILD 0

core/embed/trezorhal/lowlevel.h

@@ -26,6 +26,7 @@ secbool flash_check_option_bytes(void);
 void flash_lock_option_bytes(void);
 void flash_unlock_option_bytes(void);
 uint32_t flash_set_option_bytes(void);
+secbool flash_configure_basic_option_bytes(void);
 secbool flash_configure_option_bytes(void);
 void periph_init(void);
 secbool reset_flags_check(void);

core/embed/trezorhal/stm32u5/lowlevel.c

@@ -170,6 +170,18 @@ secbool flash_check_option_bytes(void) {
   return sectrue;
 }
 
+secbool flash_check_basic_option_bytes(void) {
+  flash_wait_and_clear_status_flags();
+
+  if ((FLASH->OPTR & FLASH_OPTR_TZEN) == 0) {
+    return secfalse;
+  }
+  if (FLASH->SECBOOTADD0R != FALSH_SECBOOTADD0R_VALUE) {
+    return secfalse;
+  }
+  return sectrue;
+}
+
 void flash_lock_option_bytes(void) {
   FLASH->NSCR |= FLASH_NSCR_OPTLOCK;  // lock the option bytes
 }
@@ -186,6 +198,37 @@ void flash_unlock_option_bytes(void) {
     ;  // wait until the flash option control register is unlocked
 }
 
+uint32_t flash_set_basic_option_bytes(void) {
+  if (flash_unlock_write() != sectrue) {
+    return 0;
+  }
+  flash_wait_and_clear_status_flags();
+  flash_unlock_option_bytes();
+  flash_wait_and_clear_status_flags();
+
+  FLASH->OPTR |= FLASH_OPTR_TZEN;
+
+  FLASH->SECBOOTADD0R = FALSH_SECBOOTADD0R_VALUE;
+
+  FLASH_WaitForLastOperation(HAL_MAX_DELAY);
+
+  FLASH->NSCR |= FLASH_NSCR_OPTSTRT;
+  uint32_t result =
+      flash_wait_and_clear_status_flags();  // wait until changes are committed
+
+  FLASH_WaitForLastOperation(HAL_MAX_DELAY);
+
+  FLASH->NSCR |= FLASH_NSCR_OBL_LAUNCH;  // begin committing changes to flash
+  result =
+      flash_wait_and_clear_status_flags();  // wait until changes are committed
+  flash_lock_option_bytes();
+
+  if (flash_lock_write() != sectrue) {
+    return 0;
+  }
+  return result;
+}
+
 uint32_t flash_set_option_bytes(void) {
   if (flash_unlock_write() != sectrue) {
     return 0;
@@ -239,6 +282,18 @@ void check_oem_keys(void) {
   ensure(((FLASH->NSSR & FLASH_NSSR_OEM2LOCK) == 0) * sectrue, "OEM2 KEY SET");
 }
 
+secbool flash_configure_basic_option_bytes(void) {
+  if (sectrue == flash_check_basic_option_bytes()) {
+    return sectrue;  // we DID NOT have to change the option bytes
+  }
+
+  do {
+    flash_set_basic_option_bytes();
+
+  } while (sectrue != flash_check_basic_option_bytes());
+  return secfalse;  // notify that we DID have to change the option bytes
+}
+
 secbool flash_configure_option_bytes(void) {
   if (sectrue == flash_check_option_bytes()) {
     return sectrue;  // we DID NOT have to change the option bytes