Update Recovery to TWRP 3.5.2-9
Boot into Recovery
Factory Reset (only needed if you are not already on Android 7.x AOSP)
フォーマット形式EXT4
Install 7.1.2 Grouper OTA-Package (Build 20210305) (md5: c0a1f205254c49355cca1d350b65e33b)
or
Install 7.1.2 Tilapia OTA-Package (Build 20210305) (md5: 0801569114aa0531d992f1004c90dc11)
Reboot into recovery
Install Open GApps (arm/7.1/pico)

俺はこれで問題ないぞ8GB