After upgrading to Big Sur on a Mac Pro 6.1 (Trash Can) on the boot process this message stop the boot for 15 sec (more or less). Searching on the web few people have the same problem but nobody figured out the issue and a potential solution. After this delay the boot proceed and finish in less than a minute.
ignoring kext cache invocation from early boot
Same problem with MacBook Air 7.1
After lot of investigation I strongly believe is related to TRIM setting. Potentially disabling trim can lead to much better boot time bit If the Mac have a stock Apple SSD, Trim is enabled by default and cannot be disabled using "sudo trimforce disable". It looks clearly like an Apple bug, but after 3 update to Big Sur is still not fixed.
There are new and coming limits to kernel extension (before full deprecation ?)
https://developer.apple.com/fr/support/kernel-extensions/
https://support.apple.com/fr-fr/guide/security/sec8e454101b/web
https://developer.apple.com/fr/support/kernel-extensions/
https://support.apple.com/fr-fr/guide/security/sec8e454101b/web