Recording to USB drive not working

[ctsmetrony]

Here is where I am with this:

T53 W
Firmware Version 96.86.0.45
Hardware Version 95.1.0.0.2.1.3
3CX PBX Standard (NOT Pro or Enterprise)

USB Pendrive, FAT32 config, is recognized by phone. Also tried FAT.

Modified cfg file with these relevant lines:

features.usb_call_recording.enable = 1
features.voice_mail_popup.enable = 0
forward.international.enable = 0
ldap.host = 0.0.0.0
linekey.1.label = 121 | Xxx Xxxxxx
linekey.10.type = 0
linekey.11.type = 0
linekey.12.type = 0
linekey.2.label = 121 | Xxx Xxxxxx
linekey.2.line = 1
linekey.3.label = RECORD

Pressing Linekey 3 on a call, LED flashed until pressed again or end call. USB has no audio file recorded on it after "recording" call.

Thanks
Jim