SIM-Unlock Samsung Galaxy S4 (SM-S975L)(TracFone/StraightTalk)

I’m trying to to Unlock this Galaxy S4 (SM-S975L)(Tracfone/StraightTalk USA)

Tried Unlock using GCKey Pro:
***NewQC Unlock Method****

#1) Log said it’s SUCCESSFUL & UNLOCKED. (***1st Attempt***)
After Reboot it’s STILL INVALID SIM CARD. (Not SIM Unlock Yet)

#2) GCKey Pro log mentioned about: (***2nd Attempt***)
New BaseBand Unlock not supported,Try downgrade modem.bin ..2752

================================================== =====
Using Version…1.0.0.0038
Selected Port ssudserd0001 = COM4
Selected Model GT-I5500
Selected Task SAMSUNG NEW-QC UNLOCK

Searching phone…

Build…M9615A-CEFWTAZM-4.0.17135

Device Detected…
model:= SM-S975L
Androids Version:= 4.3
Description Version:= jflteud-user 4.3 JSS15J S975LUDUAOF4 release-keys
Platform:= msm8960 [ qcom ] [ mdm ]
Baseband:= S975LUDUAOF4
VER:= S975LUDUAOF4/S975LTFNAOF4/S975LUDUAOF4/S975LUDUAOF4
Carrier := TFN_USA
EFS CSC := TFN
Network Mode := 0
Simstatus:= CARD_IO_ERROR
IMEI-1 = 3518920637XXXXX
ANDROID-ID = 24b62b33_351892063766633
Device is not rooted

SAMSUNG NEW-QC UNLOCK Started..
New BaseBand Unlock not supported,Try downgrade modem.bin ..2752

!!! Fail !!!!
Restart Phone if not auto…
Total Time Take…00:00:14
Log Saved
================================================== =====

Anyone have any idea which MODEM.BIN or version of baseband I should try to downgrade to unlock this Galaxy S4 (SM-S975L)?

This look like a CDMA Galaxy S4 Locked just like SPRINT USA Locked by baseband.

Someone care to comments please!!! Thanks!

Related:

  • s975l unlock cdma
  • sm-s975l unlock