Nintendo Switch Brew

Fuses: Difference between revisions

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The Nintendo Switch makes use of Tegra's fuse driver for a number of operations. This driver is mapped to physical address 0x7000F800 with a total size of 0x400 bytes and exposes several registers for fuse programming.
The Nintendo Switch uses the Tegra's fuse driver for accessing one time programmable data.


Registers from 0x7000F800 to 0x7000F800 + 0xFF can be used to directly program the hardware fuse bitmap, while registers from 0x7000F800 + 0x100 (FUSE_CHIP_REG_START_OFFSET) to 0x7000F800 + 0x3FC (FUSE_CHIP_REG_END_OFFSET) represent cached values read from certain fuses.
= Registers =
The fuse driver is mapped to physical address 0x7000F800 with a total size of 0x400 bytes and exposes several registers for fuse programming.


== Registers ==
== Erista ==
Below is a list of fuse driver registers used by the Switch's bootloaders.
Registers from 0x7000F800 to 0x7000F800 + 0xFC represent the actual fuse [[#Driver|driver]] which can be used to directly program the hardware fuse bitmap.


=== Driver registers ===
Registers from 0x7000F800 + 0x100 (FUSE_CHIP_REG_START_OFFSET) to 0x7000F800 + 0x3FC (FUSE_CHIP_REG_END_OFFSET) represent the fuse [[#Cache|cache]] which holds the sensed values of certain fuses.
 
=== Driver ===
{| class="wikitable" border="1"
{| class="wikitable" border="1"
!  Name
!  Name
Line 49: Line 52:
| [[#FUSE_WRITE_ACCESS_SW|FUSE_WRITE_ACCESS_SW]]
| [[#FUSE_WRITE_ACCESS_SW|FUSE_WRITE_ACCESS_SW]]
| 0x7000F830
| 0x7000F830
|-
| [[#FUSE_PWR_GOOD_SW|FUSE_PWR_GOOD_SW]]
| 0x7000F834
|-
|-
| [[#FUSE_PRIV2RESHIFT|FUSE_PRIV2RESHIFT]]
| [[#FUSE_PRIV2RESHIFT|FUSE_PRIV2RESHIFT]]
Line 324: Line 324:


Controls and returns the status of software writes to the fuse cache registers.
Controls and returns the status of software writes to the fuse cache registers.
==== FUSE_PWR_GOOD_SW ====
{| class="wikitable" border="1"
!  Bits
!  Description
|-
| 0
| FUSE_PWR_GOOD_SW_VAL
|}
This register is deprecated and has no effect.


==== FUSE_PRIV2RESHIFT ====
==== FUSE_PRIV2RESHIFT ====
Line 369: Line 358:
|-
|-
| 9
| 9
| FUSE_PRIV2RESHIFT_TRIG_1_SCPU_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU0_VAL
|-
|-
| 10
| 10
| FUSE_PRIV2RESHIFT_TRIG_1_SL2_TBANK_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU1_VAL
|-
|-
| 11
| 11
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU0_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU2_VAL
|-
|-
| 12
| 12
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU1_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU3_VAL
|-
|-
| 13
| 13
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU2_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK0_VAL
|-
|-
| 14
| 14
| FUSE_PRIV2RESHIFT_STATUS_1_FCPU3_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK1_VAL
|-
|-
| 15
| 15
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK0_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK2_VAL
|-
|-
| 16
| 16
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK1_VAL
|-
| 17
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK2_VAL
|-
| 18
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK3_VAL
| FUSE_PRIV2RESHIFT_STATUS_1_FL2_TBANK3_VAL
|-
| 19
| FUSE_PRIV2RESHIFT_STATUS_1_SCPU_VAL
|-
| 20
| FUSE_PRIV2RESHIFT_STATUS_1_SL2_TBANK_VAL
|}
|}


Line 473: Line 450:
Returns whether [[#Bitmap|private_key4]] is empty or not.
Returns whether [[#Bitmap|private_key4]] is empty or not.


=== Cache registers ===
=== Cache ===
{| class="wikitable" border="1"
{| class="wikitable" border="1"
!  Name
!  Name
Line 499: Line 476:
| 0x7000F918
| 0x7000F918
|-
|-
| FUSE_DAC_CRT_CALIB
| [[#FUSE_OPT_FT_REV|FUSE_OPT_FT_REV]]
| 0x7000F91C
|-
| FUSE_DAC_HDTV_CALIB
| 0x7000F920
|-
| FUSE_DAC_SDTV_CALIB
| 0x7000F924
|-
| [[#FUSE_OPT_FT_REV|FUSE_OPT_FT_REV]]
| 0x7000F928
| 0x7000F928
|-
|-
Line 528: Line 496:
| FUSE_SOC_IDDQ_CALIB
| FUSE_SOC_IDDQ_CALIB
| 0x7000F940
| 0x7000F940
|-
| FUSE_RESERVED_PRODUCTION_WP
| 0x7000F944
|-
|-
| [[#FUSE_FA|FUSE_FA]]
| [[#FUSE_FA|FUSE_FA]]
Line 582: Line 547:
| FUSE_TSENSOR2_CALIB
| FUSE_TSENSOR2_CALIB
| 0x7000F988
| 0x7000F988
|-
| FUSE_VSENSOR_CALIB
| 0x7000F98C
|-
|-
| [[#FUSE_OPT_CP_REV|FUSE_OPT_CP_REV]]
| [[#FUSE_OPT_CP_REV|FUSE_OPT_CP_REV]]
Line 654: Line 616:
| FUSE_OBS_DIS
| FUSE_OBS_DIS
| 0x7000F9E8
| 0x7000F9E8
|-
| FUSE_NOR_INFO
| 0x7000F9EC
|-
|-
| FUSE_USB_CALIB
| FUSE_USB_CALIB
Line 706: Line 665:
| 0x7000FA2C
| 0x7000FA2C
|-
|-
| FUSE_SKU_BOND_OUT_L
| FUSE_CLOCK_BOUNDOUT0
| 0x7000FA30
| 0x7000FA30
|-
|-
| FUSE_SKU_BOND_OUT_H
| FUSE_CLOCK_BOUNDOUT1
| 0x7000FA34
| 0x7000FA34
|-
| FUSE_SKU_BOND_OUT_U
| 0x7000FA38
|-
| FUSE_SKU_BOND_OUT_V
| 0x7000FA3C
|-
| FUSE_SKU_BOND_OUT_W
| 0x7000FA40
|-
|-
| FUSE_OPT_SAMPLE_TYPE
| FUSE_OPT_SAMPLE_TYPE
Line 882: Line 832:
| FUSE_RESERVED_FIELD
| FUSE_RESERVED_FIELD
| 0x7000FB54
| 0x7000FB54
|-
| FUSE_OPT_ECC_EN
| 0x7000FB58
|-
|-
| FUSE_SPARE_REALIGNMENT_REG
| FUSE_SPARE_REALIGNMENT_REG
Line 1,187: Line 1,134:
[4.0.0+] This value is no longer used during boot.
[4.0.0+] This value is no longer used during boot.


== Bitmap ==
== Mariko ==
The actual hardware fuses are stored in a bitmap and may be programmed through the fuse driver after enabling fuse programming.
Registers from 0x7000F800 to 0x7000F800 + 0x94 represent the actual fuse [[#Driver_2|driver]] which can be used to directly program the hardware fuse bitmap.
 
Registers from 0x7000F800 + 0x98 to 0x7000F800 + 0x3FC represent the fuse [[#Cache_2|cache]] which holds the sensed values of certain fuses.


Fuse numbers are relative to the start of the fuse bitmap where each element is a 4 byte word and has a redundant alias. A single fuse write operation must always write the same value to '''fuse_bitmap + ((fuse_number + 0) << 2)''' (PRIMARY_ALIAS) and '''fuse_bitmap + ((fuse_number + 1) << 2)''' (REDUNDANT_ALIAS). However, spare bits and all fuses afterwards in the fuse bitmap, no longer have a redundant alias.
=== Driver ===
Same registers as in the Erista's fuse [[#Driver|driver]].


Below is a list of common fuses used by Tegra devices (and applicable to the Switch).
=== Cache ===
{| class="wikitable" border="1"
!  Name
!  Address
|-
| FUSE_RESERVED_ODM8
| 0x7000F898
|-
| FUSE_RESERVED_ODM9
| 0x7000F89C
|-
| FUSE_RESERVED_ODM10
| 0x7000F8A0
|-
| FUSE_RESERVED_ODM11
| 0x7000F8A4
|-
| FUSE_RESERVED_ODM12
| 0x7000F8A8
|-
| FUSE_RESERVED_ODM13
| 0x7000F8AC
|-
| FUSE_RESERVED_ODM14
| 0x7000F8B0
|-
| FUSE_RESERVED_ODM15
| 0x7000F8B4
|-
| FUSE_RESERVED_ODM16
| 0x7000F8B8
|-
| FUSE_RESERVED_ODM17
| 0x7000F8BC
|-
| FUSE_RESERVED_ODM18
| 0x7000F8C0
|-
| FUSE_RESERVED_ODM19
| 0x7000F8C4
|-
| FUSE_RESERVED_ODM20
| 0x7000F8C8
|-
| FUSE_RESERVED_ODM21
| 0x7000F8CC
|-
|
| 0x7000F8D0
|-
|
| 0x7000F8D4
|-
|
| 0x7000F8D8
|-
|
| 0x7000F8DC
|-
|
| 0x7000F8E0
|-
|
| 0x7000F8E4
|-
|
| 0x7000F8E8
|-
|
| 0x7000F8EC
|-
|
| 0x7000F8F0
|-
|
| 0x7000F8F4
|-
|
| 0x7000F8F8
|-
|
| 0x7000F8FC
|-
| FUSE_PRODUCTION_MODE
| 0x7000F900
|-
| FUSE_JTAG_SECUREID_VALID
| 0x7000F904
|-
| FUSE_ODM_LOCK
| 0x7000F908
|-
| FUSE_OPT_OPENGL_EN
| 0x7000F90C
|-
| FUSE_SKU_INFO
| 0x7000F910
|-
| FUSE_CPU_SPEEDO_0_CALIB
| 0x7000F914
|-
| FUSE_CPU_IDDQ_CALIB
| 0x7000F918
|-
| FUSE_RESERVED_ODM22
| 0x7000F91C
|-
| FUSE_RESERVED_ODM23
| 0x7000F920
|-
| FUSE_RESERVED_ODM24
| 0x7000F924
|-
| FUSE_OPT_FT_REV
| 0x7000F928
|-
| FUSE_CPU_SPEEDO_1_CALIB
| 0x7000F92C
|-
| FUSE_CPU_SPEEDO_2_CALIB
| 0x7000F930
|-
| FUSE_SOC_SPEEDO_0_CALIB
| 0x7000F934
|-
| FUSE_SOC_SPEEDO_1_CALIB
| 0x7000F938
|-
| FUSE_SOC_SPEEDO_2_CALIB
| 0x7000F93C
|-
| FUSE_SOC_IDDQ_CALIB
| 0x7000F940
|-
| FUSE_RESERVED_ODM25
| 0x7000F944
|-
| FUSE_FA
| 0x7000F948
|-
| FUSE_RESERVED_PRODUCTION
| 0x7000F94C
|-
| FUSE_HDMI_LANE0_CALIB
| 0x7000F950
|-
| FUSE_HDMI_LANE1_CALIB
| 0x7000F954
|-
| FUSE_HDMI_LANE2_CALIB
| 0x7000F958
|-
| FUSE_HDMI_LANE3_CALIB
| 0x7000F95C
|-
| FUSE_ENCRYPTION_RATE
| 0x7000F960
|-
| FUSE_PUBLIC_KEY0
| 0x7000F964
|-
| FUSE_PUBLIC_KEY1
| 0x7000F968
|-
| FUSE_PUBLIC_KEY2
| 0x7000F96C
|-
| FUSE_PUBLIC_KEY3
| 0x7000F970
|-
| FUSE_PUBLIC_KEY4
| 0x7000F974
|-
| FUSE_PUBLIC_KEY5
| 0x7000F978
|-
| FUSE_PUBLIC_KEY6
| 0x7000F97C
|-
| FUSE_PUBLIC_KEY7
| 0x7000F980
|-
| FUSE_TSENSOR1_CALIB
| 0x7000F984
|-
| FUSE_TSENSOR2_CALIB
| 0x7000F988
|-
|
| 0x7000F98C
|-
| FUSE_OPT_CP_REV
| 0x7000F990
|-
| FUSE_OPT_PFG
| 0x7000F994
|-
| FUSE_TSENSOR0_CALIB
| 0x7000F998
|-
| FUSE_FIRST_BOOTROM_PATCH_SIZE
| 0x7000F99C
|-
| FUSE_SECURITY_MODE
| 0x7000F9A0
|-
| FUSE_PRIVATE_KEY0
| 0x7000F9A4
|-
| FUSE_PRIVATE_KEY1
| 0x7000F9A8
|-
| FUSE_PRIVATE_KEY2
| 0x7000F9AC
|-
| FUSE_PRIVATE_KEY3
| 0x7000F9B0
|-
| FUSE_PRIVATE_KEY4
| 0x7000F9B4
|-
| FUSE_ARM_JTAG_DIS
| 0x7000F9B8
|-
| FUSE_BOOT_DEVICE_INFO
| 0x7000F9BC
|-
| FUSE_RESERVED_SW
| 0x7000F9C0
|-
| FUSE_OPT_VP9_DISABLE
| 0x7000F9C4
|-
| FUSE_RESERVED_ODM0
| 0x7000F9C8
|-
| FUSE_RESERVED_ODM1
| 0x7000F9CC
|-
| FUSE_RESERVED_ODM2
| 0x7000F9D0
|-
| FUSE_RESERVED_ODM3
| 0x7000F9D4
|-
| FUSE_RESERVED_ODM4
| 0x7000F9D8
|-
| FUSE_RESERVED_ODM5
| 0x7000F9DC
|-
| FUSE_RESERVED_ODM6
| 0x7000F9E0
|-
| FUSE_RESERVED_ODM7
| 0x7000F9E4
|-
| FUSE_OBS_DIS
| 0x7000F9E8
|-
|
| 0x7000F9EC
|-
| FUSE_USB_CALIB
| 0x7000F9F0
|-
| FUSE_SKU_DIRECT_CONFIG
| 0x7000F9F4
|-
| FUSE_KFUSE_PRIVKEY_CTRL
| 0x7000F9F8
|-
| FUSE_PACKAGE_INFO
| 0x7000F9FC
|-
| FUSE_OPT_VENDOR_CODE
| 0x7000FA00
|-
| FUSE_OPT_FAB_CODE
| 0x7000FA04
|-
| FUSE_OPT_LOT_CODE_0
| 0x7000FA08
|-
| FUSE_OPT_LOT_CODE_1
| 0x7000FA0C
|-
| FUSE_OPT_WAFER_ID
| 0x7000FA10
|-
| FUSE_OPT_X_COORDINATE
| 0x7000FA14
|-
| FUSE_OPT_Y_COORDINATE
| 0x7000FA18
|-
| FUSE_OPT_SEC_DEBUG_EN
| 0x7000FA1C
|-
| FUSE_OPT_OPS_RESERVED
| 0x7000FA20
|-
|
| 0x7000FA24
|-
| FUSE_GPU_IDDQ_CALIB
| 0x7000FA28
|-
| FUSE_TSENSOR3_CALIB
| 0x7000FA2C
|-
| FUSE_CLOCK_BONDOUT0
| 0x7000FA30
|-
| FUSE_CLOCK_BONDOUT1
| 0x7000FA34
|-
| FUSE_RESERVED_ODM26
| 0x7000FA38
|-
| FUSE_RESERVED_ODM27
| 0x7000FA3C
|-
| FUSE_RESERVED_ODM28
| 0x7000FA40
|-
| FUSE_OPT_SAMPLE_TYPE
| 0x7000FA44
|-
| FUSE_OPT_SUBREVISION
| 0x7000FA48
|-
| FUSE_OPT_SW_RESERVED_0
| 0x7000FA4C
|-
| FUSE_OPT_SW_RESERVED_1
| 0x7000FA50
|-
| FUSE_TSENSOR4_CALIB
| 0x7000FA54
|-
| FUSE_TSENSOR5_CALIB
| 0x7000FA58
|-
| FUSE_TSENSOR6_CALIB
| 0x7000FA5C
|-
| FUSE_TSENSOR7_CALIB
| 0x7000FA60
|-
| FUSE_OPT_PRIV_SEC_EN
| 0x7000FA64
|-
|
| 0x7000FA68
|-
|
| 0x7000FA6C
|-
|
| 0x7000FA70
|-
|
| 0x7000FA74
|-
|
| 0x7000FA78
|-
| FUSE_FUSE2TSEC_DEBUG_DISABLE
| 0x7000FA7C
|-
| FUSE_TSENSOR_COMMON
| 0x7000FA80
|-
| FUSE_OPT_CP_BIN
| 0x7000FA84
|-
| FUSE_OPT_GPU_DISABLE
| 0x7000FA88
|-
| FUSE_OPT_FT_BIN
| 0x7000FA8C
|-
| FUSE_OPT_DONE_MAP
| 0x7000FA90
|-
| FUSE_RESERVED_ODM29
| 0x7000FA94
|-
| FUSE_APB2JTAG_DISABLE
| 0x7000FA98
|-
| FUSE_ODM_INFO
| 0x7000FA9C
|-
| FUSE_ARM_CRYPT_DE_FEATURE
| 0x7000FAA8
|-
|
| 0x7000FAB0
|-
|
| 0x7000FAB4
|-
|
| 0x7000FAB8
|-
|
| 0x7000FABC
|-
| FUSE_WOA_SKU_FLAG
| 0x7000FAC0
|-
| FUSE_ECO_RESERVE_1
| 0x7000FAC4
|-
| FUSE_GCPLEX_CONFIG_FUSE
| 0x7000FAC8
|-
| FUSE_PRODUCTION_MONTH
| 0x7000FACC
|-
| FUSE_RAM_REPAIR_INDICATOR
| 0x7000FAD0
|-
| FUSE_TSENSOR9_CALIB
| 0x7000FAD4
|-
| FUSE_VMIN_CALIBRATION
| 0x7000FADC
|-
| FUSE_AGING_SENSOR_CALIBRATION
| 0x7000FAE0
|-
| FUSE_DEBUG_AUTHENTICATION
| 0x7000FAE4
|-
| FUSE_SECURE_PROVISION_INDEX
| 0x7000FAE8
|-
| FUSE_SECURE_PROVISION_INFO
| 0x7000FAEC
|-
| FUSE_OPT_GPU_DISABLE_CP1
| 0x7000FAF0
|-
| FUSE_SPARE_ENDIS
| 0x7000FAF4
|-
| FUSE_ECO_RESERVE_0
| 0x7000FAF8
|-
| FUSE_RESERVED_CALIB0
| 0x7000FB04
|-
| FUSE_RESERVED_CALIB1
| 0x7000FB08
|-
| FUSE_OPT_GPU_TPC0_DISABLE
| 0x7000FB0C
|-
| FUSE_OPT_GPU_TPC0_DISABLE_CP1
| 0x7000FB10
|-
| FUSE_OPT_CPU_DISABLE
| 0x7000FB14
|-
| FUSE_OPT_CPU_DISABLE_CP1
| 0x7000FB18
|-
| FUSE_TSENSOR10_CALIB
| 0x7000FB1C
|-
| FUSE_TSENSOR10_CALIB_AUX
| 0x7000FB20
|-
|
| 0x7000FB24
|-
|
| 0x7000FB28
|-
|
| 0x7000FB2C
|-
|
| 0x7000FB30
|-
|
| 0x7000FB34
|-
| FUSE_OPT_GPU_TPC0_DISABLE_CP2
| 0x7000FB38
|-
| FUSE_OPT_GPU_TPC1_DISABLE
| 0x7000FB3C
|-
| FUSE_OPT_GPU_TPC1_DISABLE_CP1
| 0x7000FB40
|-
| FUSE_OPT_GPU_TPC1_DISABLE_CP2
| 0x7000FB44
|-
| FUSE_OPT_CPU_DISABLE_CP2
| 0x7000FB48
|-
| FUSE_OPT_GPU_DISABLE_CP2
| 0x7000FB4C
|-
| FUSE_USB_CALIB_EXT
| 0x7000FB50
|-
| FUSE_RESERVED_FIELD
| 0x7000FB54
|-
| FUSE_SPARE_REALIGNMENT_REG
| 0x7000FB7C
|-
| FUSE_SPARE_BIT_0
| 0x7000FB80
|-
| FUSE_SPARE_BIT_1
| 0x7000FB84
|-
| FUSE_SPARE_BIT_2
| 0x7000FB88
|-
| FUSE_SPARE_BIT_3
| 0x7000FB8C
|-
| FUSE_SPARE_BIT_4
| 0x7000FB90
|-
| FUSE_SPARE_BIT_5
| 0x7000FB94
|-
| FUSE_SPARE_BIT_6
| 0x7000FB98
|-
| FUSE_SPARE_BIT_7
| 0x7000FB9C
|-
| FUSE_SPARE_BIT_8
| 0x7000FBA0
|-
| FUSE_SPARE_BIT_9
| 0x7000FBA4
|-
| FUSE_SPARE_BIT_10
| 0x7000FBA8
|-
| FUSE_SPARE_BIT_11
| 0x7000FBAC
|-
| FUSE_SPARE_BIT_12
| 0x7000FBB0
|-
| FUSE_SPARE_BIT_13
| 0x7000FBB4
|-
| FUSE_SPARE_BIT_14
| 0x7000FBB8
|-
| FUSE_SPARE_BIT_15
| 0x7000FBBC
|-
| FUSE_SPARE_BIT_16
| 0x7000FBC0
|-
| FUSE_SPARE_BIT_17
| 0x7000FBC4
|-
| FUSE_SPARE_BIT_18
| 0x7000FBC8
|-
| FUSE_SPARE_BIT_19
| 0x7000FBCC
|-
| FUSE_SPARE_BIT_20
| 0x7000FBD0
|-
| FUSE_SPARE_BIT_21
| 0x7000FBD4
|-
| FUSE_SPARE_BIT_22
| 0x7000FBD8
|-
| FUSE_SPARE_BIT_23
| 0x7000FBDC
|-
| FUSE_SPARE_BIT_24
| 0x7000FBE0
|-
| FUSE_SPARE_BIT_25
| 0x7000FBE4
|-
| FUSE_SPARE_BIT_26
| 0x7000FBE8
|-
| FUSE_SPARE_BIT_27
| 0x7000FBEC
|-
| FUSE_SPARE_BIT_28
| 0x7000FBF0
|-
| FUSE_SPARE_BIT_29
| 0x7000FBF4
|-
| FUSE_SPARE_BIT_30
| 0x7000FBF8
|-
| FUSE_SPARE_BIT_31
| 0x7000FBFC
|}
 
==== FUSE_RESERVED_ODM28 ====
{| class="wikitable" border="1"
!  Bits
!  Description
|-
| 0
| RegulatorType
|}
 
= Bitmap =
The actual hardware fuses are stored in a bitmap and may be programmed through the fuse driver after enabling fuse programming.
 
Fuse numbers are relative to the start of the fuse bitmap where each element is a 4 byte word and has a redundant alias. A single fuse write operation must always write the same value to '''fuse_bitmap + ((fuse_number + 0) << 2)''' (PRIMARY_ALIAS) and '''fuse_bitmap + ((fuse_number + 1) << 2)''' (REDUNDANT_ALIAS). However, spare bits and all fuses afterwards in the fuse bitmap, no longer have a redundant alias.


== Erista ==
{| class="wikitable" border="1"
{| class="wikitable" border="1"
!  Name
!  Name
Line 2,266: Line 2,844:
This patch forces the value of [[Security_Engine|SE_TZRAM_SECURITY]] to be 0x01 instead of restoring it from the saved SE context.
This patch forces the value of [[Security_Engine|SE_TZRAM_SECURITY]] to be 0x01 instead of restoring it from the saved SE context.


== Anti-downgrade ==
= Anti-downgrade =
The first bootloader verifies [[#FUSE_RESERVED_ODM7|FUSE_RESERVED_ODM7]] to prevent downgrading.
The first bootloader verifies [[#FUSE_RESERVED_ODM7|FUSE_RESERVED_ODM7]] to prevent downgrading.
How many fuses are expected to be burnt depends the device's unit type as below.
How many fuses are expected to be burnt depends the device's unit type as below.
Retrieved from "https://switchbrew.org/wiki/Fuses"