I afraid to say that you have misremembering about the TPM on the G5.  Just try to intervene before going too far with all the troubleshooting and support inquiry. With the TPM device on the machine, Dell would included firmware support on drivers page. Here is the drivers page for your G5, there is no TPM firmware available. Here is the drivers page for your Latitude, you will find TPM firmware utility for both 1.2 and 2.0, screenshot is below. [IMAGE]
I have a G5 15 5587 machine and the TPM2.0 setting has disappeared from the bios settings a few weeks ago and now I only have PTT option under the security (with not TPM settings under the PTT). The machine is fitted with an 8th gen i7-8750H CPU which based on the intel datasheet supposed to have in-built TPM2.0 which was originally shown in the BIOS. The windows TPM manager still lists TPM2.0 driver with no issue flagged with the hardware. Reading some of the comments in other similar topics it is better to clarify that I have bought the machine in the UK. I have checked the advices on the forums and tried the below ones, but without any success:  - Legacy option ROMs & attempt legacy boot both disabled: these were always off and did not need to tweak with; - Re-set BIOS to default: did not change any of the setting I am aware of to be related to such issue; - Remove main battery and push on button for 30 sec; - Disable PTT: did not get back the TPM settings even after a re-boot;   It may be a coincidence but after tried the 3rd option above the machine did not re-boot at all and get a fault signal for the BIOS battery and was able to re-boot after replaced that battery. I would appreciate any advice on how can I have the TPM 2.0 in the BIOS again or if there is any other possible methods to resolve this issue.
G5 15 5587 TPM 2.0 disappeared and replaced by PTT