G960U 9.0 unlock problem

Hi, I just have this problem when I unlock 2 S9 G960U TMB with version 9.0 G960USQU3CSAB. First I downgrade to version 8.0 G960USQU3ARG7, then flash combination modem file. first one was unlocked fine by Z3X without any problem. The second one then show error. And the phone is stuck at black screen but has blue led flashing on top. Then I have to hold volume down+power+bixby button to make it go to download mode. I thought maybe the downgrade software step on the second one has some problems so I reflash the 9.0 firmware, then reflash combination modem file. Then I try to unlock again but has same error and phone stuck at same condition I said above. Now I stuck with this phone. Have anyone had same problem like me but already found solution? Would you please show me how to deal with it?

Here is the log
Checking Login and Password... OK
Ballance: 30 crd.
You have 30 credit(s) left. This operation takes 8 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-G960U
Android version: 9
PDA version: G960USQU3CSAB
CSC version: G960UOYN3CSAB
Phone version: G960USQU3ARJ1
Product code: SM2G960UZKATMB
CSC country code: USA
CSC sales code: TMB
Phone SN: R58M36CMMZT
IMEI: 3569150939*****
HW version: REV1.1
RF cal date: 2019.03.23
Chip name: SDM845
Modem board: SDM845
Security patch: 2019-01-01
Boot Warranty bit: 0
SIM State: ABSENT
Searching Samsung diag port... detected COM490
Reading phone info... OK
Reading data from phone... error (0), skip
Rebooting phone... OK
Waiting ADB device... OK
Rebooting phone... OK
Waiting ADB device... timeout
Phone not found