平臺：MT6771
版本：Android 10.0
ADB版本：1.0.41
1.打開開發者選項，勾選OEM unlocking,USB debugging,
2.adb reboot bootloader(開機鍵和音量+鍵進入recovery模式，上下選fastboot mode)
進入fastboot mode模式
3.fastboot flashing unlock
按音量+鍵解鎖
4.fastboot reboot fastboot
此步驟請不要選擇任何選項，耐心等待，出現fastbootd界面
5.fastboot delete-logical-partition product
6.fastboot -S 100M flash system D:\BaiduYunDownload\signed_signed-aosp_arm64-img-6473
483\system.img
刷入google signed system.img
7.fastboot reboot bootloader
8.fastboot flashing lock
重新上鎖，不鎖開不了機
9.fastboot reboot
重啓
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指令執行記錄
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>adb
reboot bootloader
adb server version (40) doesn't match this client (41); killing...
* daemon started successfully
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot flashing unlock
(bootloader) Start unlock flo
w
OKAY [ 7.809s]
Finished. Total time: 7.816s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot reboot fastboot
Rebooting into fastboot OKAY [ 0.006s]
< waiting for any device >
Finished. Total time: 16.133s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot delete-logical-partition product
Deleting 'product' OKAY [ 0.006s]
Finished. Total time: 0.009s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot -S 100M flash system D:\BaiduYunDownload\signed_signed-aosp_arm64-img-6473
483\system.img
Invalid sparse file format at header magic
Resizing 'system' OKAY [ 0.003s]
Sending sparse 'system' 1/12 (93956 KB) OKAY [ 3.059s]
Writing 'system' OKAY [ 3.004s]
Sending sparse 'system' 2/12 (102396 KB) OKAY [ 3.528s]
Writing 'system' OKAY [ 3.264s]
Sending sparse 'system' 3/12 (102396 KB) OKAY [ 3.451s]
Writing 'system' OKAY [ 3.226s]
Sending sparse 'system' 4/12 (97964 KB) OKAY [ 3.284s]
Writing 'system' OKAY [ 3.081s]
Sending sparse 'system' 5/12 (102396 KB) OKAY [ 3.448s]
Writing 'system' OKAY [ 3.229s]
Sending sparse 'system' 6/12 (102396 KB) OKAY [ 3.531s]
Writing 'system' OKAY [ 3.185s]
Sending sparse 'system' 7/12 (102396 KB) OKAY [ 3.459s]
Writing 'system' OKAY [ 3.250s]
Sending sparse 'system' 8/12 (102396 KB) OKAY [ 3.437s]
Writing 'system' OKAY [ 3.249s]
Sending sparse 'system' 9/12 (102396 KB) OKAY [ 3.395s]
Writing 'system' OKAY [ 3.289s]
Sending sparse 'system' 10/12 (102396 KB) OKAY [ 3.371s]
Writing 'system' OKAY [ 3.166s]
Sending sparse 'system' 11/12 (102396 KB) OKAY [ 3.374s]
Writing 'system' OKAY [ 3.186s]
Sending sparse 'system' 12/12 (64452 KB) OKAY [ 2.123s]
Writing 'system' OKAY [ 4.009s]
Finished. Total time: 82.042s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot reboot bootloader
Rebooting into bootloader OKAY [ 0.001s]
Finished. Total time: 0.003s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot flashing lock
(bootloader) Start lock flow
OKAY [ 6.811s]
Finished. Total time: 6.818s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>fas
tboot reboot
Rebooting OKAY [ 0.002s]
Finished. Total time: 0.007s
C:\Users\Administrator\Desktop\platform-tools_r30.0.1-windows\platform-tools>
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參考：https://blog.csdn.net/qq_24883353/article/details/106280528