I would say that L3 is more a fallback for when L1 isn't available. <edit> The last time I looked into Netflix's use of widewine (Which was about a year ago, s

I would say that L3 is more a fallback for when L1 isn't available. <edit> The last time I looked into Netflix's use of widewine (Which was about a year ago, so everything could of changed since) L3 is only used to protect their SD streams, L1 is required for HD, but L1 could still protect a SD stream. What I mean is L1 could be used for HD and SD where L3 is only used for SD. But you are free to implement it how ever you like (dependant on the contracts you have with content producers / rights holders). </edit> Even with a unlocked bootloader with custom BL/Rom L1 streams are decrypted and decoded within a Trusted Execution Environment (Basically the SoC in your Android device) and then send directly to the screen from there. Unlocking the bootloader and running a custom rom shouldn't effect the "trusted" state of the TEE so you should be able to decode L1 content just fine.