Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Kext-Dev-Mode=1

LightBulbFun

LightBulbFun

macrumors 68030
Original poster
Nov 17, 2013
2,808
3,125
London UK
I was thinking about the fact that in Yosemite You have to use kext-dev-mode=1 to Load Unsigned kexts now every one rites it to pram and the issue that if the Pram gets cleared the system can fail to boot now I was thinking why cant u put kext-dev-mode=1 in the com.apple.boot.plist insted? reseting the pram wont reset that plist so it solves the issue that if pram is reset system failure could happen? I Put this in the mac pro forum as thats were the command is most used :cool::apple: So if some one could tell me if u can put it in the com.apple.boot.plist insted of pram thanks :)
 
S

Skvo

macrumors newbie
Jun 20, 2014
7
6
LightBulbFun said:
So if some one could tell me if u can put it in the com.apple.boot.plist insted of pram thanks :)
Click to expand...
Use in Terminal:

sudo /usr/libexec/PlistBuddy -c "Set :'Kernel Flags' 'kext-dev-mode=1'" /Library/Preferences/SystemConfiguration/com.apple.Boot.plist
 
LightBulbFun

LightBulbFun

macrumors 68030
Original poster
Nov 17, 2013
2,808
3,125
London UK
It works

i can Confirm that it Dose work I Have an SSD in my MBP with the trim hack and I was able to use the methord above to add kext-dev-mode=1 to the com.apple.boot.plist and clear my PRAM and still boot up sucsefly with out eny hick ups and during verbouse booting i can see kext-dev-mode=1 listed in my boot args So this should solve the issue with kext signing and the risk of it being enabled when its disabled altho i am not sure if an OS update would reset the com.apple.boot.plist file?
 
crjackson2134

crjackson2134

macrumors 601
Mar 6, 2013
4,823
1,948
Charlotte, NC
That's a great catch, are there any known drawbacks? Does it affect boot times? Perhaps Cindori could use this information somehow to enhance TE. Perhaps including an option to set this mode with a slider or button.
 
mikeboss

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
YES!!! this totally works. and there aren't any drawbacks as far as I can tell. Cindori definitely needs to implement this option. I cleared nvram using the "nvram -c" command plus I used the option-command-p-r keys and Yosemite did still boot as if everything was normal. of course TRIM is still enabled :cool:
 
Last edited:
crjackson2134

crjackson2134

macrumors 601
Mar 6, 2013
4,823
1,948
Charlotte, NC
mikeboss said:
YES!!! this totally works. and there aren't any drawbacks as far as I can tell. Cindori definitely needs to implement this option. I cleared nvram using the "nvram -c" command plus I used the option-command-p-r keys and Yosemite did still boot as if everything was normal. of course TRIM is still enbaled :cool:
Click to expand...

Awesome, going to set this on next session. :)

UPDATE: So I just ran this command and reset the NVRAM through 4 cycles and all is well. Seems like this is a great fix.
 
Last edited:
matthewtoney

matthewtoney

macrumors regular
Aug 17, 2009
183
1
Charlotte, NC
crjackson2134 said:
Awesome, going to set this on next session. :)

UPDATE: So I just ran this command and reset the NVRAM through 4 cycles and all is well. Seems like this is a great fix.
Click to expand...

Fantastic! This makes me feel much better about using Trim Enabler in Yosemite. To each their own opinion, but disabling the kext signing thing itself just doesn't bug me.
 
mikeboss

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
hah! I don't know since when, but Trim Enabler already does modify the com.apple.Boot.plist and adds the "kext-dev-mode=1" line.
 
LightBulbFun

LightBulbFun

macrumors 68030
Original poster
Nov 17, 2013
2,808
3,125
London UK
mikeboss said:
hah! I don't know since when, but Trim Enabler already does modify the com.apple.Boot.plist and adds the "kext-dev-mode=1" line.
Click to expand...

then tell me why befor I rote it to the plist when I Reset the PRAM the MacBook Pro failed to boot with the somthings broken prohibeted sign Yet when I did add it to the com.apple.boot.plist my self it worked no matter how meny times i cleared the PRAM boot with nvram -c and comand optoin P R?
 
Gav Mack

Gav Mack

macrumors 68020
Jun 15, 2008
2,193
22
Sagittarius A*
Can anyone with the Sintech card + Apple blade confirm that even though trim is enabled booting off the real thing after a pram reset with signing re-enabled with you still get the no entry sign on boot?
 
mikeboss

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
LightBulbFun said:
then tell me why befor I rote it to the plist when I Reset the PRAM the MacBook Pro failed to boot with the somthings broken prohibeted sign Yet when I did add it to the com.apple.boot.plist my self it worked no matter how meny times i cleared the PRAM boot with nvram -c and comand optoin P R?
Click to expand...

as I wrote: I don't know since when Trim Enabler modifies com.apple.boot.plist. it sure didn't do this from the start. I tested it about an hour ago (on a fresh install of OS X Yosemite with a freshly downloaded version of TE) and I found the file modified after enabling TRIM. also the setting survived "nvram -c" and option-command-p-r.
 
ibarnett

ibarnett

macrumors regular
Aug 20, 2010
240
67
Gold Coast, Australia
Gav Mack said:
Can anyone with the Sintech card + Apple blade confirm that even though trim is enabled booting off the real thing after a pram reset with signing re-enabled with you still get the no entry sign on boot?
Click to expand...

Why would this happen?
Did it happen to you?
I installed mine yesterday (Sintech + Apple Blade) , displays as "Apple SSD" & trim is active through Yosemite automatically. I had previously uninstalled Trim Enabler.
To be honest I don't want to try a pram reset to find out!
 
Gav Mack

Gav Mack

macrumors 68020
Jun 15, 2008
2,193
22
Sagittarius A*
ibarnett said:
Why would this happen?
Did it happen to you?
I installed mine yesterday (Sintech + Apple Blade) , displays as "Apple SSD" & trim is active through Yosemite automatically. I had previously uninstalled Trim Enabler.
To be honest I don't want to try a pram reset to find out!
Click to expand...

No but my Sintech is ordered and I'm in hunting mode for the blade. I think my kexts may have to be done for the handoff card upgrade so I was curious as to whether it will stop the boot if the wifi/BT LE card was installed or is it only bootable devices on the OS X boot volume such as ahci, fw, usb etc which give you the no entry sign

I presume the blade is rather good :D
 
ibarnett

ibarnett

macrumors regular
Aug 20, 2010
240
67
Gold Coast, Australia
Gav Mack said:
I presume the blade is rather good :D
Click to expand...

It's just awesome!
I really don't see anything being an issue booting after a reset.
I have the bluetooth stuff as well from Macvidcards & had no issues prior to installing the Sintech & blade.
Having spent all the time cloning etc I don't want to waste time with another install - so I will wait before another pram reset.
 
Gav Mack

Gav Mack

macrumors 68020
Jun 15, 2008
2,193
22
Sagittarius A*
ibarnett said:
It's just awesome!
I really don't see anything being an issue booting after a reset.
I have the bluetooth stuff as well from Macvidcards & had no issues prior to installing the Sintech & blade.
Having spent all the time cloning etc I don't want to waste time with another install - so I will wait before another pram reset.
Click to expand...

:jealous: I need the 1tb part to replace my twin 840 Evo's and having played with the 1tb nMP and its disk performance in OS X and Windows and laughed at 'ludicrous speed' I am really going to enjoy that upgrade after!

Suggests to me it's only boot devices that bring up the no entry and I'm very happy with that.
 
VirtualRain

VirtualRain

macrumors 603
Aug 1, 2008
6,304
118
Vancouver, BC
mikeboss said:
as I wrote: I don't know since when Trim Enabler modifies com.apple.boot.plist. it sure didn't do this from the start. I tested it about an hour ago (on a fresh install of OS X Yosemite with a freshly downloaded version of TE) and I found the file modified after enabling TRIM. also the setting survived "nvram -c" and option-command-p-r.
Click to expand...

Indeed... Trim Enabler did modify my com.apple.boot.plist when I tried it earlier this evening, but the plist file doesn't look formatted properly (viewing it in TextEdit). Maybe it gets rid of a bunch of unnecessary stuff in the file while updating it or replaces it with a very sparse version. Not exactly best practice IMHO but it seems to work.
 
Cindori

Cindori

macrumors 68040
Jan 17, 2008
3,527
378
Sweden
Hi all
I am aware of this but it does not work 100%.
I have had users contact me who have had the plist set with kext-dev-mode=1 but still receiving "invalid signature, omitting" and unable to boot. Also, I'm still not sure whether it can reset on OS updates.

So since it does not seem to apply for all users, I am choosing to refer to the PRAM in my support article, since it seems to be the lower bound on expectation.

Btw, Trim Enabler already uses both methods anyway (pram and plist) for maximum probability of success. You don't need to do these steps if you are using Trim Enabler.
 
Last edited:
mikeboss

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
okay, I just tested this again. did a fresh install of Yosemite, installed Trim Enabler, zapped pram/cleared NVRAM. everything was working fine. I then installed the 10.10.1 update and the machine didn't boot anymore. exactly like cindori pointed out, this doesn't work 100% reliable. once more, I know why I got an Apple/SAMSUNG PCIe SSD for my main system...
 
Cindori

Cindori

macrumors 68040
Jan 17, 2008
3,527
378
Sweden
VirtualRain said:
So, when updating OS X Yosemite, is it best to turn Trim Enabler Off, Update, then Re-Enable Trim?
Click to expand...

Since Trim Enabler also sets the nvram, which is not reset on updates, there is a pretty low probability for any issues to occur (I would dare say near impossible). However, I still recommend it as a precaution.
 
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom