eFuse
Applies to BL702, BL704 and BL706
Size: 1Kbit
eFuse is one time programmable memory. It’s mostly used to store things like MAC Address, encryption keys and all other stuff, which are not possible to change after it being burned into eFuse.
In case of BL70X eFuse, once you burn the bit in eFuse, it’s not possible to revert it. You can also write/read lock of specific eFuse slots/areas.
The structure of the eFuse is available in Bouffalo’s SDK and bfl_mcu_tools (file efuse_cfg_keys.py), although, it doesn’t contains all properties.
NOTE: This still work in progress and those information still can be not true
The slots ef_key_slot_4_w0 and ef_key_slot_4_w1 seems not to be used by any code.
If encryption is not used, slots from ef_key_slot_0_w0 to ef_key_slot_3_w3 can be free for the user application.
| Name | Byte Offset | Bit index | Length (bits) | Used in | Notes | Verified |
|---|---|---|---|---|---|---|
| ef_sf_aes_mode | 0 (0x0) | 0 | 2 | TBD | 0 - disabled, 1 - 32 bit AES key, 2 - 48 bit key, 3 - 64 bit key | No |
| ef_sboot_sign_mode | 0 (0x0) | 2 | 2 | No | ||
| ef_sboot_en | 0 (0x0) | 4 | 2 | No | ||
| ef_cpu_enc_en | 0 (0x0) | 7 | 1 | No | ||
| trim_enable | 0 (0x0) | 12 | 1 | No | ||
| ef_sw_usage_1 | 0 (0x0) | 13 | 1 | No | ||
| ef_sdu_dis | 0 (0x0) | 14 | 1 | No | ||
| ef_ble_dis | 0 (0x0) | 15 | 1 | No | ||
| ef_wifi_dis | 0 (0x0) | 16 | 1 | No | ||
| ef_0_key_enc_en | 0 (0x0) | 17 | 1 | No | ||
| ef_sf_dis | 0 (0x0) | 19 | 1 | No | ||
| ef_cpu_rst_dbg_dis | 0 (0x0) | 21 | 1 | No | ||
| ef_se_dbg_dis | 0 (0x0) | 22 | 1 | No | ||
| ef_efuse_dbg_dis | 0 (0x0) | 23 | 1 | No | ||
| ef_dbg_jtag_dis | 0 (0x0) | 26 | 2 | No | ||
| ef_dbg_mode | 0 (0x0) | 28 | 4 | No | ||
| ef_dbg_pwd_low | 4 (0x4) | 0 | 32 | No | ||
| ef_dbg_pwd_high | 8 (0x8) | 0 | 32 | No | ||
| ef_ana_trim_0 | 12 (0xC) | 0 | 32 | No | ||
| ef_sw_usage_0 | 16 (0x10) | 0 | 32 | No | ||
| bootrom_protect | 16 (0x10) | 0 | 1 | No | ||
| uart_log_disable | 16 (0x10) | 1 | 1 | No | ||
| sdio_pin_init | 16 (0x10) | 2 | 1 | No | ||
| disable_cci_coexist | 16 (0x10) | 3 | 1 | No | ||
| xtal_type | 16 (0x10) | 4 | 3 | No | ||
| pll_clk | 16 (0x10) | 7 | 3 | No | ||
| hclk_div | 16 (0x10) | 10 | 1 | No | ||
| bclk_div | 16 (0x10) | 11 | 1 | No | ||
| flash_clk_type | 16 (0x10) | 12 | 3 | No | ||
| flash_clk_div | 16 (0x10) | 15 | 1 | No | ||
| flash_cfg | 16 (0x10) | 16 | 2 | No | ||
| flash_pwr_delay | 16 (0x10) | 18 | 2 | No | ||
| tz_boot | 16 (0x10) | 20 | 1 | No | ||
| encrypted_tz_boot | 16 (0x10) | 21 | 1 | No | ||
| hbn_check_sign | 16 (0x10) | 22 | 1 | No | ||
| keep_dbg_port_closed | 16 (0x10) | 23 | 1 | No | ||
| mediaboot_disable | 16 (0x10) | 24 | 1 | No | ||
| uartboot_disable | 16 (0x10) | 25 | 1 | No | ||
| sdioboot_disable | 16 (0x10) | 26 | 1 | No | ||
| hbn_jump_disable | 16 (0x10) | 27 | 1 | No | ||
| jtag_switch | 16 (0x10) | 28 | 1 | No | ||
| jtag_init | 16 (0x10) | 29 | 1 | No | ||
| qfn40 | 16 (0x10) | 30 | 1 | No | ||
| debug_log_reopen | 16 (0x10) | 31 | 1 | No | ||
| ef_wifi_mac_low | 20 (0x14) | 0 | 32 | BootROM, eflash_loader, boot2 | Lower part of MAC Address (BT/WIFI), also used as ChipID | Yes |
| ef_wifi_mac_high | 24 (0x18) | 0 | 32 | BootROM, eflash_loader, boot2 | Higher part of MAC Address (BT/WIFI), also used as ChipID | Yes |
| ef_key_slot_0_w0 | 28 (0x1C) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [0:8 bytes of hash] | Yes |
| ef_key_slot_0_w1 | 32 (0x20) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [8:16 bytes of hash] | Yes |
| ef_key_slot_0_w2 | 36 (0x24) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [16:24 bytes of hash] | Yes |
| ef_key_slot_0_w3 | 40 (0x28) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [24:32 bytes of hash] | Yes |
| ef_key_slot_1_w0 | 44 (0x2C) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [32:40 bytes of hash] | Yes |
| ef_key_slot_1_w1 | 48 (0x30) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [40:48 bytes of hash] | Yes |
| ef_key_slot_1_w2 | 52 (0x34) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [48:56 bytes of hash] | Yes |
| ef_key_slot_1_w3 | 56 (0x38) | 0 | 32 | TBD | Public key hash, when ef_sboot_sign_mode is 1 [56:64 bytes of hash] | Yes |
| ef_key_slot_2_w0 | 60 (0x3C) | 0 | 32 | TBD | AES key (aes_mode == 1, 2, 3) | Yes |
| ef_key_slot_2_w1 | 64 (0x40) | 0 | 32 | TBD | AES key (aes_mode == 1, 2, 3) | Yes |
| ef_key_slot_2_w2 | 68 (0x44) | 0 | 32 | TBD | AES key (aes_mode == 1, 2, 3) | Yes |
| ef_key_slot_2_w3 | 72 (0x48) | 0 | 32 | TBD | AES key (aes_mode == 1, 2, 3) | Yes |
| ef_key_slot_3_w0 | 76 (0x4C) | 0 | 32 | TBD | AES key (aes_mode == 2, 3) | Yes |
| ef_key_slot_3_w1 | 80 (0x50) | 0 | 32 | TBD | AES key (aes_mode == 2, 3) | Yes |
| ef_key_slot_3_w2 | 84 (0x54) | 0 | 32 | TBD | AES key (aes_mode == 3) | Yes |
| ef_key_slot_3_w3 | 88 (0x58) | 0 | 32 | TBD | AES key (aes_mode == 3) | Yes |
| ef_key_slot_4_w0 | 92 (0x5C) | 0 | 32 | TBD | Empty? | No |
| ef_key_slot_4_w1 | 96 (0x60) | 0 | 32 | TBD | Empty? | No |
| ef_key_slot_4_w2 | 100 (0x64) | 0 | 32 | TBD | Customer VID (0xFFFF0000) & PID (0x0000FFFF) | Yes |
| ef_key_slot_4_w3 | 104 (0x68) | 0 | 32 | TBD | Chip VID (0xFFFF0000) & PID (0x0000FFFF) | Yes |
| ef_key_slot_5_w0 | 108 (0x6C) | 0 | 32 | TBD | Optional MAC Address slot (low) | Yes |
| ef_key_slot_5_w1 | 112 (0x70) | 0 | 32 | TBD | Optional MAC Address slot (high) | Yes |
| ef_key_slot_5_w2 | 116 (0x74) | 0 | 32 | TBD | Device Info structure (TBD) | Yes |
| ef_key_slot_5_w3 | 120 (0x78) | 0 | 32 | TBD | CapCode (TBD) | No |
| wr_lock_key_slot_4_l | 124 (0x7C) | 13 | 1 | No | ||
| wr_lock_key_slot_5_l | 124 (0x7C) | 14 | 1 | No | ||
| wr_lock_boot_mode | 124 (0x7C) | 15 | 1 | No | ||
| wr_lock_dbg_pwd | 124 (0x7C) | 16 | 1 | No | ||
| wr_lock_sw_usage_0 | 124 (0x7C) | 17 | 1 | No | ||
| wr_lock_wifi_mac | 124 (0x7C) | 18 | 1 | Write lock for MAC Address eFuse (by default burned from factory) | Yes | |
| wr_lock_key_slot_0 | 124 (0x7C) | 19 | 1 | No | ||
| wr_lock_key_slot_1 | 124 (0x7C) | 20 | 1 | No | ||
| wr_lock_key_slot_2 | 124 (0x7C) | 21 | 1 | No | ||
| wr_lock_key_slot_3 | 124 (0x7C) | 22 | 1 | No | ||
| wr_lock_key_slot_4_h | 124 (0x7C) | 23 | 1 | No | ||
| wr_lock_key_slot_5_h | 124 (0x7C) | 24 | 1 | No | ||
| rd_lock_dbg_pwd | 124 (0x7C) | 25 | 1 | No | ||
| rd_lock_key_slot_0 | 124 (0x7C) | 26 | 1 | No | ||
| rd_lock_key_slot_1 | 124 (0x7C) | 27 | 1 | No | ||
| rd_lock_key_slot_2 | 124 (0x7C) | 28 | 1 | No | ||
| rd_lock_key_slot_3 | 124 (0x7C) | 29 | 1 | No | ||
| rd_lock_key_slot_4 | 124 (0x7C) | 30 | 1 | No | ||
| rd_lock_key_slot_5 | 124 (0x7C) | 31 | 1 | No |