[Sony Xperia X Compact Questions & Answers] mbc07:
That's only half of the story. The DRM Fix library has two working modes, and what defines which mode it'll pick depends if you have your unique device key (that get wiped when you unlock the bootloader) flashed in an alternate TA Unit. You can extract your device key and then flash it on an alternate unit as long as you have a TA backup taken before unlocking the bootloader (the RootKernel utility from [MENTION=357342]tobias.waldvogel[/MENTION] ships with the required tools to extract and flash your device key).

On the "normal" mode (DRM Fix + device key flashed on alternate TA unit) you have exactly the same functionality you would get on a bootloader locked device with its TA intact, everything works. But, in case you don't have your device key flashed into an alternate TA unit (e.g. unlocked the bootloader without backing up the TA first, lost backup, etc), then DRM Fix will work in emulation mode. On emulation mode, most features that check for DRM will still work (e.g. camera algorithms, X-Reality Engine, etc) but some specific DRM features that requires the device key (e.g. Widevine L1 decryption, HDCP on Screen Mirroring, etc.) won't work. As it was increasingly more difficult to find exploits for newer devices and firmwares, that's the mode most DRM Fix users utilize, I guess.

Now, how to tell a DRM Fix restored device apart a device with intact TA is a little tricky, but you basically have 3 situations:

• Bootloader locked device, security test in Service Menu shows both Widevine and CKB as [OK] [Active] => stock device with TA partition intact

• Security test in Service Menu shows [unknown] or [generic error] on Widevine or CKB (or both) => TA partition wiped, DRM Fix not applied

• Bootloader unlocked device, security test in Service Menu shows both Widevine and CKB as [OK] [Active] => TA partition wiped, DRM Fix applied

When a device has the DRM Fix applied, it's not possible to tell if it's working in normal or emulation mode until you try something that requires the device keys (e.g. Widevine L1 or HDCP on Screen Mirroring). If it works, DRM Fix is in normal mode, otherwise it's in emulation mode. Also, you can't trust the "Bootloader Status" info on the Security Test of the Service menu to tell whether the bootloader was unlocked or not, as it'll always report "locked" if you have the DRM Fix applied. A safe way to tell the bootloader status is (re)booting the device and observing if the "Your device has been unlocked and can't be trusted" message appears before the Sony logo. If that message appears, the bootloader was unlocked.

You'll also find many people debating whether FIDO Keys being provisioned or not actually indicates the status of the DRM Fix, but from my experience, they aren't related. Fact is that I had FIDO Keys not provisioned on my Xperia X right after I turned it on for the first time (brand new device, had just taken it from the box), but upon registering a fingerprint, FIDO Keys became Provisioned again. Same thing occurred after I backed up my TA with the dirtycow exploit then unlocked the bootloader, FIDO Keys became not provisioned but after enrolling a fingerprint they became Provisioned again, even through I hadn't installed DRM Fix yet at that point.

And to finish, keep in mind all I said on this post is only valid for Xperia devices that launched before Xperia XZ Premium. With XZ Premium launch, Sony reworked many parts of the DRM protection and the original DRM Fix from previous devices didn't work at all. Another user eventually developed a new DRM Fix solution for those newer devices, but it works completely different and I have absolutely zero experience with it.