Hervé

Yes, boot with Enoch option cpus=1 (or Clover equivalent), then replace your current VoodooPS2Controller kext with this one and you will no longer experience this systematic KP.

What model of nVidia, is it the 940M as listed in some HP published specs? What about the rest like audio, LAN, wireless, SD card reader, etc. ? You have a Skylake platform, so you have no other choice but El Capitan (Skylake support introduced in 10.11.1 kernel and Skylake HD520/HD530 support just got introduced in 10.11.4). Keep in mind that there are no Skylake MacBook for the moment (only 27" iMac), that's expected later on this year so you're ahead of the game. Hardly any Skylake laptops actually run OS X with complete support. There's only limited success afaik. If your GeForce proved unsupported, you'd have to rely on the integrated HD520 graphics; that should work on the basis that 10.11.4 supports HD520/HD530. All in all, you're going to need a lot of patience until Apple releases Skylake-based MacBook laptops.

Or use: sudo kextcache -system-prelinked-kernel That usually works fine on 1st attempt.

You can forget about ML on a Broadwell or Skylake platform. ML supports Intel CPUs up to Haswell generation and, for those 4th gen CPUs, only in 10.8.5. You will have to target Yosemite 10.10 (minimum) or current El Capitan 10.11, knowing that there is limited support for Skylake platforms at the moment... For the rest, well, you'll have to post your system's specs.

You need the patched AppleHDA kext (in /S/L/E) or Clover on-the-fly AppleHDA patch + the dummy IDT kext (in /L/E or /S/L/E) for audio to work. Alternative, the attached patched AppleHDA kext (from Yos) will work fine on its own from /S/L/E. IDT-76e7_patched_AppleHDA_v272.18.kext.zip

What exactly is your issue? Battery reported as goosed/needing replacement or just trouble obtaining the status in the Finder's bar? If the former, i.e. you're getting the consistent and permanent "dying battery" message, then you probably need to consider replacing your ageing battery. If the latter, check the battery management kext you use and consider Rehabman's ACPIBatteryManager v1.5x/v1.60.x. What battery management kext are you using?

The DSDT applies to all E6230, no matter their CPU model; it's the generated speedsted-related SSDT that is CPU-specific.

ML is totally obsolete these days (Apple dropped support for it) and does not support Broadwell platforms afaik. As such, you would not be able to natively run ML on a Latitude E3550. Opt for a much newer and free version like Yosemite or El Capitan; they run absolutely fine, especially on recent hardware like Broadwell or (gradually) Skylake platforms. If I remember well, Broadwell support was introduced in Yosemite 10.10.2 or 10.10.3. Haswell CPUs were supported in ML, but only in ultimate version 10.8.5.

Can you please post your specs? If you installed Mavericks with myHack, you can copy/paste the output of Terminal command lspci -nn.

You can grab the patched DSDT off my E6230 guide to obtain your desired behaviour, assuming you've disabled hibernation of course. In terms of patch, you basically need to mod the _PRW methods of the EHCx/XHC/GLAN/HDEF devices to set (0x--, 0x03) or (0x--, 0x04) to (0x--, 0x00) as detailed in Rehabman's 6 Series/7 Series patches list. Or you can apply Rehabman's patches if you prefer.

It would seem you copied the Enoch installation package on your USB installer (that's for a future use once OS X is installed on your disk partition) but you did not install the bootloader on your USB installer ! It's never going to boot without that key step. Ok, so your iMac reported the app could not run because from an unknown developper but you can't just ignore that message. On your iMac, go to your Security PrefPane and either authorise the app to run once or modify your security settings to allow downloaded app from anywhere. Do think of calling on OS X built-in help if you encounter error messages that you don't fully understand. It's kinda basic...

Check out that you don't have 2 x PS2 controller kext, like one in /L/E and another in /S/L/E or in CLOVER/kexts/10.11 or CLOVER/kexts/Other. Dr Hurt's kext definitely works as tested on E6220, E6230, E6440 or E7740. So, you need to find out what you did wrong. Detailed list of your actions and returned results could help... Are you sure you've installed this kext?

I literally just posted revised packs in my thread with an updated DSDT. The revised 10.11 pack also includes Dr Hurt's VoodooPS2Controller which does not trigger KP on startup. Make sure to follow the guide rigorously.

Seems the revised kext is not taken into account. Place it in /L/E, then repair permissions and rebuild your cache with the usual Terminal commands.

Since most people appear unable to use the Search facility of the forum and/or unable to click a posted link , here's a ISO Layout-enabled copy of Dr Hurt's VoodooPS2Controller that works with all existing versions of El Capitan. VoodooPS2Controller.kext.zip Works perfectly on my E6220, E6230 and E6440 so I expect it to be Ok with other models of the E6x20, E6x30 and E6x40 too.

You'll find it in the 10.11.4 update dedicated thread in the Support->Mac OS X section.

You'll retain all VoodooPS2 features with the version I linked right under that post Jake linked you to.

Ok, I just grabbed the old D620n to try it out. I was able to complete 1st boot of freshly installed 10.8(.0) with -x boot flag. I prepared my myHack v3.3.1 10.8 installer with bootpack of the guide. Which version of ML are you starting with? My guide does stipulate that with subsequent versions such as 10.8.2 or 10.8.3, I was never able to (re)boot, but I'm about to test after a direct update to 10.8.5 through combo update.

After initial installation, yes, but it seems you never got to that stage, did you? Anyway, that stuff is about 3yrs old and I can't remember it all; though I do remember that the D620n was a bastard to get going...

Maybe the boot loader associates/injects the wrong device description to the PCI id, though it would be surprising... According to the literature those nVidia (vendor 0x10de) chips have the following device ids: Quadro NVS 135M = 0x042b GeForce 8400M GS = 0x0427

Maybe your DSDT contains the reference to the NVS 13M, I don't know. It's just cosmetic. There's an article in the Articles page of the web site that explains how you can change this; I invite you to read it. Your GPU device will be located at address 0x00010000 under a name like GFX0 or VID or AGP, something of that line. You can easily image your existing OS X installation partition from the USB installer. All you need to do is boot to main installer screen, then go to Utilities->Disk Utility and make an image of your HDD partition on the USB key. If there is not sufficient space, reduce the existing HDD partition and make one of the necessary space to hold the desired image. Something like 16Go should be more than enough.

Is the bootpack (/Extra folder) present on the ML partition? You can check it out from the USB installer by going to Terminal and typing: ls -la /Volumes/<ML partition name>

No, that's graphics not initialising. Try with boot option GraphicsEnabler=No.

Why do you use the -x flag to boot in safe mode? Boot with -f -v flags instead. Make sure that myHack installed the bootpack on your ML standard installations, I fear it did not... Reboot your USB installer, then, once at the installation main screen, go to Utilities and run myHack->Install Extra->my own, targeting your local HDD ML partition, not the USB installer. You should then be able to run standard ML (still with boot option arch=x86_64) without graphics support for your NVS 110M.

And refer to this thread for full keyboard layout recognition.