Mac build AOSP branch android-9.0.0_r1 error

run ./flash-all.sh FAILED (remote: flash write back vrl failure).
mac build AOSP branch android-9.0.0_r1.

Sending ‘xloader’ (151 KB) OKAY [ 0.013s]
Writing ‘xloader’ FAILED (remote: flash write back vrl failure)
Finished. Total time: 0.382s

At which step of the flash?

android out dir:/Volumes/Android/androidP/out/target/product/hikey960
target reported max download size of 471859200 bytes
Sending ‘xloader’ (151 KB)…
OKAY [ 0.011s]
Writing ‘xloader’…
FAILED (remote: flash write back vrl failure)
Finished. Total time: 0.402s
target reported max download size of 471859200 bytes
Sending ‘ptable’ (196 KB)…
OKAY [ 0.011s]
Writing ‘ptable’…
OKAY [ 0.023s]
Finished. Total time: 0.064s
target reported max download size of 471859200 bytes
Sending ‘fastboot’ (3346 KB)…
OKAY [ 0.085s]
Writing ‘fastboot’…
OKAY [ 0.035s]
Finished. Total time: 0.150s
rebooting into bootloader
OKAY [ 0.013s]
Finished. Total time: 0.022s
< waiting for any device >
target reported max download size of 471859200 bytes
Sending ‘nvme’ (128 KB)…
OKAY [ 0.010s]
Writing ‘nvme’…
OKAY [ 0.041s]
Finished. Total time: 0.083s
target reported max download size of 471859200 bytes
Sending ‘fw_lpm3’ (212 KB)…
OKAY [ 0.012s]
Writing ‘fw_lpm3’…
OKAY [ 0.012s]
Finished. Total time: 0.054s
target reported max download size of 471859200 bytes
Sending ‘trustfirmware’ (145 KB)…
OKAY [ 0.011s]
Writing ‘trustfirmware’…
OKAY [ 0.013s]
Finished. Total time: 0.054s
target reported max download size of 471859200 bytes
Sending ‘boot’ (10110 KB)…
OKAY [ 0.254s]
Writing ‘boot’…
OKAY [ 0.094s]
Finished. Total time: 0.378s
target reported max download size of 471859200 bytes
Sending ‘dts’ (14 KB)…
OKAY [ 0.007s]
Writing ‘dts’…
OKAY [ 0.015s]
Finished. Total time: 0.051s
target reported max download size of 471859200 bytes
Sending sparse ‘system’ 1/2 (460796 KB)…
OKAY [ 11.146s]
Writing ‘system’ 1/2…
OKAY [ 3.618s]
Sending sparse ‘system’ 2/2 (415804 KB)…
OKAY [ 10.172s]
Writing ‘system’ 2/2…
OKAY [ 3.145s]
Finished. Total time: 28.111s
target reported max download size of 471859200 bytes
Sending ‘cache’ (56 KB)…
OKAY [ 0.008s]
Writing ‘cache’…
OKAY [ 0.115s]
Finished. Total time: 0.153s
target reported max download size of 471859200 bytes
Sending ‘userdata’ (4832 KB)…
OKAY [ 0.121s]
Writing ‘userdata’…
OKAY [ 0.531s]
Finished. Total time: 0.682s
Rebooting…

AFAIK this specific error can be ignored (I’ve already seen this error on my side).
https://android.googlesource.com/device/linaro/hikey/+/master/installer/hikey960/README#32