Power on from external display doesn't work anymore (Security Update 2021-007)

Thanl you, Chris!

I'll do as soon as I'll get enough time (and patience) to answer questions like: "sure that no black-out is going on?" or "why not to reinstall macOS?" and so on... ;)

Anyway, I'll update this thread, if they will solve the issue, even if I'm afraid that:

1. something could change within the next update 2021-008 or 2022-001
2. or it will be the same forever for security reasons. Possibly they "closed a door" before booting, for security purposes.

We'll see.

Have a great day you too!

Hi Chris,

thank you for your answer. My problem is not about "waking up" my MBP, but swtching it on from power off (shut down), as I use to do daily (I know, is not so common, but I l like).

No need for power adapter, as my external display (Philips 328P6VUBREB - https://www.displayspecifications.com/en/model/461a13f2) provides enough power to my MBP.

Before Security Update 2021-007 everything worked perfectly: my MBP and external displays switched off; then power on the display and boot window on the external display (white apple, then accounts).

After applying the last Security Update, there's no way to get the same behaviour, even if I disconnect any other device from my MBP.

To power on my MBP I now can only lift the MBP lid.

Thank you again!

Hi Chris,

the released Security Update (2021-008) solved the issue.

Have a good day!

Daniele