Questions regarding kext management

[jonessl]

RehabMan, thanks. I will not be able to look at this again for some weeks.

In the meantime, you often say a checkered kext history requires a reinstall of OSX to clear things up. If I simply delete kexts from S/L/E and rebuild the cache is that enough, or does OSX get in a mess anyhow?

Also, if I ever want to get (say) the vanilla IOBluetoothFamily.kext, is there a way that I can get it from the OSX dmg? (Please).

 

[RehabMan]

[Guide] Airport - PCIe Half Mini v2

RehabMan, thanks. I will not be able to look at this again for some weeks.

In the meantime, you often say a checkered kext history requires a reinstall of OSX to clear things up. If I simply delete kexts from S/L/E and rebuild the cache is that enough, or does OSX get in a mess anyhow?

Also, if I ever want to get (say) the vanilla IOBluetoothFamily.kext, is there a way that I can get it from the OSX dmg? (Please).

If you've only added kexts and you know where they went, then it is easy to delete them (rebuild cache) and avoid a clean install.

But if you've installed replacements/patches/rollbacks of system kexts and didn't keep careful documentation about what you did and didn't keep backups of the originals (complicated by system updates in between), then things get messy and a fresh install is recommended.

For most system kexts (that you don't have backups for), you can retrieve them from the Unibeast USB's /System/Library/Extensions, provided the USB is of the same version you current have installed (eg. no updates since the fresh install), but even that is a little sketchy as the kexts there are often incomplete. For example, AppleHDA on the USB is lacking much of the non-english language files and so restoring that kext from the USB might impact non-english installations.

In general, it is best to keep backups of system kexts before you tamper with them, such that restoration is easy and 100% certain. You could always do a fresh install (+updates) to a spare partition, just to use as a source for vanilla kexts.

 

[jonessl]

[Guide] Airport - PCIe Half Mini v2

If you've only added kexts and you know where they went, then it is easy to delete them (rebuild cache) and avoid a clean install.

But if you've installed replacements/patches/rollbacks of system kexts and didn't keep careful documentation about what you did and didn't keep backups of the originals (complicated by system updates in between), then things get messy and a fresh install is recommended.

For most system kexts (that you don't have backups for), you can retrieve them from the Unibeast USB's /System/Library/Extensions, provided the USB is of the same version you current have installed (eg. no updates since the fresh install), but even that is a little sketchy as the kexts there are often incomplete. For example, AppleHDA on the USB is lacking much of the non-english language files and so restoring that kext from the USB might impact non-english installations.

In general, it is best to keep backups of system kexts before you tamper with them, such that restoration is easy and 100% certain. You could always do a fresh install (+updates) to a spare partition, just to use as a source for vanilla kexts.

Brilliant, thanks!

 

[jonessl]

[Guide] Airport - PCIe Half Mini v2

You could always do a fresh install (+updates) to a spare partition, just to use as a source for vanilla kexts.

I really like this idea. Is there a "brain" like the Windows Registry that gets fouled up by kexts, or is it simply the whole cache being rebuilt provides the brain (in other words, if kexts are changed, and the original kexts later replaced with Kext Wizard, and the cache rebuilt, would the system be "returned to new"). [Taking a fairly fresh system, with very few mods, only say 10 kexts ever having been changed.]

If it is just the kexts themselves and the cache building, this would mean I could more easily investigate my BT (with the kexts being pulled from another install, when I wanted them).

Also, do I need to worry/reset nvram (if so, how).

 

[RehabMan]

[Guide] Airport - PCIe Half Mini v2

I really like this idea. Is there a "brain" like the Windows Registry that gets fouled up by kexts, or is it simply the whole cache being rebuilt provides the brain (in other words, if kexts are changed, and the original kexts later replaced with Kext Wizard, and the cache rebuilt, would the system be "returned to new"). [Taking a fairly fresh system, with very few mods, only say 10 kexts ever having been changed.]

If it is just the kexts themselves and the cache building, this would mean I could more easily investigate my BT (with the kexts being pulled from another install, when I wanted them).

Also, do I need to worry/reset nvram (if so, how).

This is getting off-topic.

There is not really an equivalent to the Windows registry in OS X. Instead, such "config data" is spread all over the file system in various plist/config files.

You should not need to reset/rebuild anything unless you have an issue, or, for example, modify the set of kexts outside official installers (eg. sending kexts to the trash).

 

[jonessl]

[Guide] Airport - PCIe Half Mini v2

This is getting off-topic.

There is not really an equivalent to the Windows registry in OS X. Instead, such "config data" is spread all over the file system in various plist/config files.

You should not need to reset/rebuild anything unless you have an issue, or, for example, modify the set of kexts outside official installers (eg. sending kexts to the trash).

Sorry, I realize that. The site is also a place of learning, so please feel free to move this (and let me know where).

One final question. I have deleted kexts in the past, by dropping them to the trash, and then using Kext Wizard to install a replacement. (I make a copy of the original first). Is this the wrong way of doing things? I've tried looking around and not found a guide to removing kexts, as opposed to installing htem, of which there are many.

On topic again, it might be that my deletions of kexts by trashing them might explain my problems. Yes or no?

 

[RehabMan]

[Guide] Airport - PCIe Half Mini v2

Sorry, I realize that. The site is also a place of learning, so please feel free to move this (and let me know where).

One final question. I have deleted kexts in the past, by dropping them to the trash, and then using Kext Wizard to install a replacement. (I make a copy of the original first). Is this the wrong way of doing things?

That works without doing anything special simply because of the order. Kext Wizard rebuilds cache after the install. If you do it in the opposite order, you'd have problems.

I've tried looking around and not found a guide to removing kexts, as opposed to installing htem, of which there are many.

Removing kexts is easy. They are simply directories, so you simply remove the directory that contains them from /S/L/E. But you must rebuild cache because the cache will still be holding on to the original configuration prior to the deletion.

On topic again, it might be that my deletions of kexts by trashing them might explain my problems. Yes or no?

If you're using kernel cache, and you remove kexts from /S/L/E without rebuilding it, it is as if you never deleted them, until something else triggers a cache rebuild.

 

[RehabMan]

Moved off-topic from networking to new thread.

 

[jonessl]

If you're using kernel cache, and you remove kexts from /S/L/E without rebuilding it, it is as if you never deleted them, until something else triggers a cache rebuild.

Good, thanks, and thanks for responding!

I've done it the right way, but will implement your vanilla install idea to a spare partition so I can get vanilla kexts whenever I need them. However, all this will now need to wait a month!

I'll keep my eyes open in the hope toleda comes up with something on the BT front. I appreciate the apparent simplicity of the appropriate identities, it is just sad that the results are not good for an identical card someone else has got working!