[Mate 8 Q&A, Help & Troubleshooting] n0my:
I think the factory image already contains those partitions.

The file was loaded successfully

Device found: KWG5T16919XXXXXX

IMEI: 8631970XXXXXXXX
Build number: :NRD90M test-keys
Product model: EVA-AL10

Erasing nvme partition
ERASE partition nvme ...FAILED
Cannot get FBlock info from device
Activating backdoor: DONE

Erasing nvme partition
Partition nvme erased

Erasing oeminfo partition
Partition oeminfo erased

Erasing modemnvm_backup partition
Partition modemnvm_backup erased

Erasing modemnvm_factory partition
Partition modemnvm_factory erased

Erasing modemnvm_system partition
Partition modemnvm_system erased

Erasing cust partition
Partition cust erased

Erasing misc partition
Partition misc erased

Erasing userdata partition
Partition userdata erased

Writing xloader partition with file fastbootimage/sec_xloader.img
xloader partition UPDATE ...OK

Writing ptable partition with file fastbootimage/ptable.img
ptable partition UPDATE ...OK

Writing fastboot partition with file fastbootimage/sec_fastboot.img
fastboot partition UPDATE ...OK

Writing dts partition with file fastbootimage/sec_dt.img
dts partition UPDATE ...OK

Writing fw_lpm3 partition with file fastbootimage/sec_lpm3.img
fw_lpm3 partition UPDATE ...OK

Writing sensorhub partition with file fastbootimage/sec_sensorhub.img
sensorhub partition UPDATE ...OK

Writing fw_hifi partition with file fastbootimage/sec_hifi.img
fw_hifi partition UPDATE ...OK

Writing teeos partition with file fastbootimage/sec_trustedcore.img
teeos partition UPDATE ...OK

Writing recovery partition with file fastbootimage/sec_recovery.img
recovery partition UPDATE ...OK

Erasing cache partition
Partition cache erased

Writing cache partition with file fastbootimage/cache.img
cache partition UPDATE ...OK

Writing boot partition with file fastbootimage/sec_boot.img
boot partition UPDATE ...OK

Writing nvme partition with file fastbootimage/nvme.img
nvme partition UPDATE ...OK

Writing trustfirmware partition with file fastbootimage/sec_bl31.bin
trustfirmware partition UPDATE ...OK

Writing modem partition with file fastbootimage/sec_balong_modem.bin
modem partition UPDATE ...OK

Writing modem_dtb partition with file fastbootimage/sec_modem_dt.img
modem_dtb partition UPDATE ...OK

Writing modemnvm_update partition with file fastbootimage/nv.bin
modemnvm_update partition UPDATE ...OK

Writing modem_dsp partition with file fastbootimage/sec_lphy.bin
modem_dsp partition UPDATE ...OK

Writing modem_om partition with file fastbootimage/modem_fs.img
modem_om partition UPDATE ...OK

Writing modemnvm_img partition with file fastbootimage/modem_nv.img
modemnvm_img partition UPDATE ...OK

Writing 3rdmodem partition with file fastbootimage/3rdmodem.img
3rdmodem partition UPDATE ...OK

Writing 3rdmodemnvm partition with file fastbootimage/3rdmodemnvm.img
3rdmodemnvm partition UPDATE ...OK

Writing 3rdmodemnvmbkp partition with file fastbootimage/3rdmodemnvmbkp.img
3rdmodemnvmbkp partition UPDATE ...OK

Erasing userdata partition
Partition userdata erased

Writing userdata partition with file fastbootimage/userdata.img
userdata partition UPDATE ...OK

Writing system partition with file fastbootimage/system.img
system partition UPDATE ...OK

Writing splash2 partition with file fastbootimage/splash2.img
splash2 partition UPDATE ...OK

Writing frp partition with file fastbootimage/frp.img
frp partition UPDATE ...OK

Writing oeminfo partition with file fastbootimage/oeminfo.mbn
oeminfo partition UPDATE ...OK

Erasing cust partition
Partition cust erased

Writing cust partition with file fastbootimage/cust_factory.img
cust partition UPDATE ...OK

Writing secure_storage partition with file fastbootimage/secure_storage.img
secure_storage partition UPDATE ...OK
Software written
Writing device finished OK

Maybe they are faulty.

Does anyone have those partitions for P9?