I think you misunderstood this topic. This is not about the Netflix L1 issue (which I don't have fortunately). It is about the Xiaomi L1 certificate. It is quite common that the certificate "disappears" for some reason (a bug probably). Just check all the "Xiaomi phone forums" ... Luckily Miui allows us to download a new certificate. And now we know how to do that on this device too. Thanks to
@Felk96
They're the same issue. The Netflix missing L1 happened because the device L1 certificate had gone missing randomly (downgraded to L3), which is not a netflix isolated issue. Netflix doesn't have a L1 certificate, the L1 certificate is on your device, Netflix just read/detect what Widevine level are you at.
Like you said, on xiaomi devices with a fingerprint sensor, we only had to redownload the certificate in the security settings. However in out of the box Global version Pad 5, just by restarting, you will get a new L1 Certificate. I had checked this using DRM Info, whenever your L1 disappears, check DRM Info and it will says L3, do a restart, and check it again with DRMinfo, it'll now show L1 again, until the bug reappears.
The "clear netflix app" I mentioned (as one of many application that checks Widvine L* certificate), was just because of the specific behavior of netflix, that they're stuck with the last lowest certificate the phone had, even if you got your L1 certificate back. Netflix in particular will still assume you're using the last L3 certificate, and won't detect your new L1 until you cleared the app and logging back in. Other streaming apps like PrimeVideo does not behave like that, as long as your current widevine is at level 1 they'll show HD contents again.
As I don't really use other streaming service than those two, I can't really sure that other streaming service would behave like netflix or like prime video. And what I were trying to say is, even if you had your L1 certificate back (from either methods), but the service still won't play HD content back, try clearing app's data.
