OS X 10.10 Yosemite DP1 kernel(cache)

Apple released OS X v10.10 Yosemite Developer Preview 1 (Build 14A238x) to its Mac developers and soon after the release notes showed up on pastebin.com. And no. That wasn’t me. That was someone else. No idea who it was but anyway. The DP1 initiated a lot of (press) coverage about the new (flat) look and feel, and that is great for end-users and the like, but we hackers are far more interested in the boring stuff. Hidden deep under the hood of OS X 10.10 Yosemite DP1 and thus here goes.


Apple renamed mach_kernel to kernel and also moved it out of the root. Eliminating the need to hide it during the installation process. Which failed a couple of times already, and then people could easily rm the file. Well. Not anymore, because now it is put away in: /System/Library/Kernels making the accidental removal of the kernel virtually impossible. Oh and here is a tip. I found this change by looking at: /usr/standalone/BootCaches.plist and here is a snipped of that file.

<key>Kernelcache v1.3</key>
	<key>Preferred Compression</key>


The above snippet also gave away that Apple is still using the same version/name/path for the kernel cache, but hold on. There is also a new property called Preferred Compression. Set to lzvn. Which is new. Overriding the previously used lzss compression method. But looking at the code, I think that you can either remove or rename lzvn to lzss and then kextcache will re-create a new kernelcache with lzss. Which is a must have for legacy boot loaders like Chameleon, Chimera and RevoBoot because without support for lzvn or renamed property value, this piece of code in drivers.c will error out with: “kernel compression is bad!

if (kernel_header->signature == OSSwapBigToHostConstInt32('comp'))
	if (kernel_header->compressType != OSSwapBigToHostConstInt32('lzss'))
		error("kernel compression is bad\n");
		return -1;

Yikes! I love using kernel cache. It makes booting up your Mac/hack so much faster. How do we fix this?


I started with a simple grep for lzvn in the extensions directory, resulting in two matches. One in AppleFSCompressionZlib.kext
And one in IOGraphics.kext
Here we also find a reference to lzvn.opcode_table which appears to be a 2KB data table. And since kextcache creates the kernel cache, it had to have the same sort of code. Bingo. Here it is.
The good news is that the source code of both IOGraphics.kext and kextcache should become publicly available. Well. Not right now, because Apple is, as usual, very slow with updating opensource.apple.com. Their reasons are unknown, but it is most likely security related. And even then. I mean. Look at what happened with XCPM in the mach_kernel. No source was ever shared. Why? No idea.

Also. The 2KB opcode tables are not the same. In fact. All three are different. The question now is what to do. Wait or dig deeper and try to write our own lzvn code. The problem is that I don’t even have the time to finish this blog article…


Some of you may wonder why Clover can boot with kernel cache while other, legacy, boot loaders cannot. The answer is rather simple. Clover loads: /usr/standalone/i386/boot.efi and this file adds support for lzvn with yet another (also different) 2 KB opcode.table Oops. I almost forgot it. This is where _lzvn_decode can be found in boot.efi
Support for lzss is still there so we can use both of them.

What is next?

I extracted the 2 KB opcode.table from boot.efi, now also available from dropbox (all four of them) and then I disassembled _lzvn_decode. Well. Here you go. Yup. This the one from boot.efi.

   19780:	55                   	push   %rbp
   19781:	48 89 e5             	mov    %rsp,%rbp
   19784:	57                   	push   %rdi
   19785:	56                   	push   %rsi
   19786:	48 89 cf             	mov    %rcx,%rdi
   19789:	48 89 d6             	mov    %rdx,%rsi
   1978c:	4c 89 c2             	mov    %r8,%rdx
   1978f:	4c 89 c9             	mov    %r9,%rcx
   19792:	53                   	push   %rbx
   19793:	41 54                	push   %r12
   19795:	48 8d 1d 24 ee 06 00 	lea    0x6ee24(%rip),%rbx        # 0x885c0
   1979c:	48 31 c0             	xor    %rax,%rax
   1979f:	4d 31 e4             	xor    %r12,%r12
   197a2:	48 83 ee 08          	sub    $0x8,%rsi
   197a6:	0f 82 92 02 00 00    	jb     0x19a3e
   197ac:	48 8d 4c 0a f8       	lea    -0x8(%rdx,%rcx,1),%rcx
   197b1:	48 39 ca             	cmp    %rcx,%rdx
   197b4:	0f 87 84 02 00 00    	ja     0x19a3e
   197ba:	4c 0f b6 0a          	movzbq (%rdx),%r9
   197be:	4c 8b 02             	mov    (%rdx),%r8
   197c1:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   197c5:	48 83 c2 01          	add    $0x1,%rdx
   197c9:	48 39 ca             	cmp    %rcx,%rdx
   197cc:	0f 87 6c 02 00 00    	ja     0x19a3e
   197d2:	4c 0f b6 0a          	movzbq (%rdx),%r9
   197d6:	4c 8b 02             	mov    (%rdx),%r8
   197d9:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   197dd:	0f 1f 00             	nopl   (%rax)
   197e0:	49 c1 e9 06          	shr    $0x6,%r9
   197e4:	4a 8d 54 0a 02       	lea    0x2(%rdx,%r9,1),%rdx
   197e9:	48 39 ca             	cmp    %rcx,%rdx
   197ec:	0f 87 4c 02 00 00    	ja     0x19a3e
   197f2:	4d 89 c4             	mov    %r8,%r12
   197f5:	49 0f cc             	bswap  %r12
   197f8:	4d 89 e2             	mov    %r12,%r10
   197fb:	49 c1 e4 05          	shl    $0x5,%r12
   197ff:	49 c1 e2 02          	shl    $0x2,%r10
   19803:	49 c1 ec 35          	shr    $0x35,%r12
   19807:	49 c1 ea 3d          	shr    $0x3d,%r10
   1980b:	49 c1 e8 10          	shr    $0x10,%r8
   1980f:	49 83 c2 03          	add    $0x3,%r10
   19813:	4e 8d 1c 08          	lea    (%rax,%r9,1),%r11
   19817:	4d 01 d3             	add    %r10,%r11
   1981a:	49 39 f3             	cmp    %rsi,%r11
   1981d:	73 3d                	jae    0x1985c
   1981f:	4c 89 04 07          	mov    %r8,(%rdi,%rax,1)
   19823:	4c 01 c8             	add    %r9,%rax
   19826:	49 89 c0             	mov    %rax,%r8
   19829:	4d 29 e0             	sub    %r12,%r8
   1982c:	0f 82 0c 02 00 00    	jb     0x19a3e
   19832:	49 83 fc 08          	cmp    $0x8,%r12
   19836:	72 54                	jb     0x1988c
   19838:	4e 8b 0c 07          	mov    (%rdi,%r8,1),%r9
   1983c:	49 83 c0 08          	add    $0x8,%r8
   19840:	4c 89 0c 07          	mov    %r9,(%rdi,%rax,1)
   19844:	48 83 c0 08          	add    $0x8,%rax
   19848:	49 83 ea 08          	sub    $0x8,%r10
   1984c:	77 ea                	ja     0x19838
   1984e:	4c 01 d0             	add    %r10,%rax
   19851:	4c 0f b6 0a          	movzbq (%rdx),%r9
   19855:	4c 8b 02             	mov    (%rdx),%r8
   19858:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   1985c:	4d 85 c9             	test   %r9,%r9
   1985f:	74 1f                	je     0x19880
   19861:	4c 8d 5e 08          	lea    0x8(%rsi),%r11
   19865:	44 88 04 07          	mov    %r8b,(%rdi,%rax,1)
   19869:	48 83 c0 01          	add    $0x1,%rax
   1986d:	49 39 c3             	cmp    %rax,%r11
   19870:	0f 84 cb 01 00 00    	je     0x19a41
   19876:	49 c1 e8 08          	shr    $0x8,%r8
   1987a:	49 83 e9 01          	sub    $0x1,%r9
   1987e:	75 e5                	jne    0x19865
   19880:	49 89 c0             	mov    %rax,%r8
   19883:	4d 29 e0             	sub    %r12,%r8
   19886:	0f 82 b2 01 00 00    	jb     0x19a3e
   1988c:	4c 8d 5e 08          	lea    0x8(%rsi),%r11
   19890:	4e 0f b6 0c 07       	movzbq (%rdi,%r8,1),%r9
   19895:	49 83 c0 01          	add    $0x1,%r8
   19899:	44 88 0c 07          	mov    %r9b,(%rdi,%rax,1)
   1989d:	48 83 c0 01          	add    $0x1,%rax
   198a1:	49 39 c3             	cmp    %rax,%r11
   198a4:	0f 84 97 01 00 00    	je     0x19a41
   198aa:	49 83 ea 01          	sub    $0x1,%r10
   198ae:	75 e0                	jne    0x19890
   198b0:	4c 0f b6 0a          	movzbq (%rdx),%r9
   198b4:	4c 8b 02             	mov    (%rdx),%r8
   198b7:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   198bb:	49 c1 e9 06          	shr    $0x6,%r9
   198bf:	4a 8d 54 0a 01       	lea    0x1(%rdx,%r9,1),%rdx
   198c4:	48 39 ca             	cmp    %rcx,%rdx
   198c7:	0f 87 71 01 00 00    	ja     0x19a3e
   198cd:	49 c7 c2 38 00 00 00 	mov    $0x38,%r10
   198d4:	4d 21 c2             	and    %r8,%r10
   198d7:	49 c1 e8 08          	shr    $0x8,%r8
   198db:	49 c1 ea 03          	shr    $0x3,%r10
   198df:	49 83 c2 03          	add    $0x3,%r10
   198e3:	e9 2b ff ff ff       	jmpq   0x19813
   198e8:	49 c1 e9 06          	shr    $0x6,%r9
   198ec:	4a 8d 54 0a 03       	lea    0x3(%rdx,%r9,1),%rdx
   198f1:	48 39 ca             	cmp    %rcx,%rdx
   198f4:	0f 87 44 01 00 00    	ja     0x19a3e
   198fa:	49 c7 c2 38 00 00 00 	mov    $0x38,%r10
   19901:	49 c7 c4 ff ff 00 00 	mov    $0xffff,%r12
   19908:	4d 21 c2             	and    %r8,%r10
   1990b:	49 c1 e8 08          	shr    $0x8,%r8
   1990f:	49 c1 ea 03          	shr    $0x3,%r10
   19913:	4d 21 c4             	and    %r8,%r12
   19916:	49 c1 e8 10          	shr    $0x10,%r8
   1991a:	49 83 c2 03          	add    $0x3,%r10
   1991e:	e9 f0 fe ff ff       	jmpq   0x19813
   19923:	49 c1 e9 03          	shr    $0x3,%r9
   19927:	49 83 e1 03          	and    $0x3,%r9
   1992b:	4a 8d 54 0a 03       	lea    0x3(%rdx,%r9,1),%rdx
   19930:	48 39 ca             	cmp    %rcx,%rdx
   19933:	0f 87 05 01 00 00    	ja     0x19a3e
   19939:	4d 89 c2             	mov    %r8,%r10
   1993c:	49 81 e2 07 03 00 00 	and    $0x307,%r10
   19943:	49 c1 e8 0a          	shr    $0xa,%r8
   19947:	4d 0f b6 e2          	movzbq %r10b,%r12
   1994b:	49 c1 ea 08          	shr    $0x8,%r10
   1994f:	49 c1 e4 02          	shl    $0x2,%r12
   19953:	4d 09 e2             	or     %r12,%r10
   19956:	49 c7 c4 ff 3f 00 00 	mov    $0x3fff,%r12
   1995d:	49 83 c2 03          	add    $0x3,%r10
   19961:	4d 21 c4             	and    %r8,%r12
   19964:	49 c1 e8 0e          	shr    $0xe,%r8
   19968:	e9 a6 fe ff ff       	jmpq   0x19813
   1996d:	48 83 c2 01          	add    $0x1,%rdx
   19971:	48 39 ca             	cmp    %rcx,%rdx
   19974:	0f 87 c4 00 00 00    	ja     0x19a3e
   1997a:	4d 89 c2             	mov    %r8,%r10
   1997d:	49 83 e2 0f          	and    $0xf,%r10
   19981:	eb 1f                	jmp    0x199a2
   19983:	48 83 c2 02          	add    $0x2,%rdx
   19987:	48 39 ca             	cmp    %rcx,%rdx
   1998a:	0f 87 ae 00 00 00    	ja     0x19a3e
   19990:	4d 89 c2             	mov    %r8,%r10
   19993:	49 c1 ea 08          	shr    $0x8,%r10
   19997:	49 81 e2 ff 00 00 00 	and    $0xff,%r10
   1999e:	49 83 c2 10          	add    $0x10,%r10
   199a2:	49 89 c0             	mov    %rax,%r8
   199a5:	4d 29 e0             	sub    %r12,%r8
   199a8:	4e 8d 1c 10          	lea    (%rax,%r10,1),%r11
   199ac:	49 39 f3             	cmp    %rsi,%r11
   199af:	0f 83 d7 fe ff ff    	jae    0x1988c
   199b5:	49 83 fc 08          	cmp    $0x8,%r12
   199b9:	0f 83 79 fe ff ff    	jae    0x19838
   199bf:	e9 c8 fe ff ff       	jmpq   0x1988c
   199c4:	49 83 e0 0f          	and    $0xf,%r8
   199c8:	4a 8d 54 02 01       	lea    0x1(%rdx,%r8,1),%rdx
   199cd:	eb 14                	jmp    0x199e3
   199cf:	49 c1 e8 08          	shr    $0x8,%r8
   199d3:	49 81 e0 ff 00 00 00 	and    $0xff,%r8
   199da:	49 83 c0 10          	add    $0x10,%r8
   199de:	4a 8d 54 02 02       	lea    0x2(%rdx,%r8,1),%rdx
   199e3:	48 39 ca             	cmp    %rcx,%rdx
   199e6:	77 56                	ja     0x19a3e
   199e8:	4e 8d 1c 00          	lea    (%rax,%r8,1),%r11
   199ec:	49 f7 d8             	neg    %r8
   199ef:	49 39 f3             	cmp    %rsi,%r11
   199f2:	77 23                	ja     0x19a17
   199f4:	4e 8d 1c 1f          	lea    (%rdi,%r11,1),%r11
   199f8:	4e 8b 0c 02          	mov    (%rdx,%r8,1),%r9
   199fc:	4f 89 0c 03          	mov    %r9,(%r11,%r8,1)
   19a00:	49 83 c0 08          	add    $0x8,%r8
   19a04:	73 f2                	jae    0x199f8
   19a06:	4c 89 d8             	mov    %r11,%rax
   19a09:	48 29 f8             	sub    %rdi,%rax
   19a0c:	4c 0f b6 0a          	movzbq (%rdx),%r9
   19a10:	4c 8b 02             	mov    (%rdx),%r8
   19a13:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   19a17:	4c 8d 5e 08          	lea    0x8(%rsi),%r11
   19a1b:	4e 0f b6 0c 02       	movzbq (%rdx,%r8,1),%r9
   19a20:	44 88 0c 07          	mov    %r9b,(%rdi,%rax,1)
   19a24:	48 83 c0 01          	add    $0x1,%rax
   19a28:	49 39 c3             	cmp    %rax,%r11
   19a2b:	74 14                	je     0x19a41
   19a2d:	49 83 c0 01          	add    $0x1,%r8
   19a31:	75 e8                	jne    0x19a1b
   19a33:	4c 0f b6 0a          	movzbq (%rdx),%r9
   19a37:	4c 8b 02             	mov    (%rdx),%r8
   19a3a:	42 ff 24 cb          	jmpq   *(%rbx,%r9,8)
   19a3e:	48 31 c0             	xor    %rax,%rax
   19a41:	41 5c                	pop    %r12
   19a43:	5b                   	pop    %rbx
   19a44:	5e                   	pop    %rsi
   19a45:	5f                   	pop    %rdi
   19a46:	5d                   	pop    %rbp
   19a47:	c3                   	retq 

Anyone willing to have a go with it? Yes. You will need to convert it and figure out how to get it going, but we are hackers. Right?

Kernelcache header data

I checked the header data of the new kernelcache, a few days ago already, and noticed that it had changed. It used to start with the mach_header_64 data (28 bytes):

struct mach_header_64 {
	uint32_t	magic;		/* mach magic number identifier */
	cpu_type_t	cputype;	/* cpu specifier */
	cpu_subtype_t	cpusubtype;	/* machine specifier */
	uint32_t	filetype;	/* type of file */
	uint32_t	ncmds;		/* number of load commands */
	uint32_t	sizeofcmds;	/* the size of all the load commands */
	uint32_t	flags;		/* flags */
	uint32_t	reserved;	/* reserved */

Which is defined in: /usr/include/mach-o/loader.h but now it starts with the pre-linked kernel header:

#define PLATFORM_NAME_LEN  (64)
#define ROOT_PATH_LEN     (256)

// prelinkVersion value >= 1 means KASLR supported
typedef struct prelinked_kernel_header {
    uint32_t  signature;
    uint32_t  compressType;
    uint32_t  adler32;
    uint32_t  uncompressedSize;
    uint32_t  compressedSize;
    uint32_t  prelinkVersion;
    uint32_t  reserved[10];
    char      platformName[PLATFORM_NAME_LEN];	// unused
    char      rootPath[ROOT_PATH_LEN];		// unused
    char      data[0];
} PrelinkedKernelHeader;

This structure is defined in kernelcache.h which is part of kext-tools and it used to come right after the mach_header_64 data, but not anymore. Easily fixed in the boot loader.


I was wrong. Only the kernel cache in the BaseSystem.dmg is missing the mach_header_64 data. It’s still there in: /System/Library/Caches/com.apple.kext.caches/Startup/kernelcache
Problem sorted.


I found a new boot argument called kcsuffix in the kextcache binary, which can be used to add… well you’ve guessed it already, add a suffix to the kernelcache.

I also found three references to .development and a strange one called /AppleInternal

I ran a few tests with kcsuffix=.development and that worked, because I noticed that the usual kextcache -Boot -U / at boot time now uses the added suffix.

Also. This bit is something you should know by now, but some people seem to be confused by it. Let’s try one more time. Ok. We already learned that
unsigned or improperly signed kexts will not be loaded in Yosemite, and that this strict checking can be disabled by adding a boot argument (kext-dev-mode=1) but you may not even need it. Not when the unsigned kext is listed in AppleKextExcludeList.kext Then you won’t have to use: kext-dev-mode=1

Quite simple isn’t it 😉

39 thoughts on “OS X 10.10 Yosemite DP1 kernel(cache)

  1. That looks pretty straightforward. I’ll give it a shot this evening if no one else has gotten around to it.

      • I have a strong, perhaps even irrational dislike for inline assembly and AT&T syntax. I haven’t gotten to it quite yet though I might have time right now. I’d disassemble that to Intel syntax, fix all the branches, compile it with nasm and add to the makefile to link it. I suppose it could be fun to rewrite it in C. I’ll pull it up in IDA and see how it goes. (No license at the moment, so no decompiler). I took a quick look through RevoBoot, it should be trivial to add the new path for 10.10.

      • By the way, my kernelcache (in 10.10) starts with mach_header_64. I’ve rebuilt it a few times; no change.

      • Well I failed to notice all these bootloaders are only x86. That leaves me with a few options, and the hacker in me would rather just change the calling conventions and link at runtime than port it to C (or i386 assembly for that matter).

      • Found some time to work on this today. Got the decompression working (in 64 bit user space). Linker is mostly done, should have time to test this weekend.

      • Didn’t get to work on it this weekend. The only thing left to do is to add some code for swapping to long mode and back. Shouldn’t take more than a few minutes. I’ll put the code on github tonight either way.

  2. I do not know if this is possible or within your realm of interest at all however there is a segment of us Mac Pro 1,1 & 2,1 owners, in an attempt to bleed every minute of life we can from our admittedly aging though still very competent machines ,that have become reliant on a “home-brew” Tiamos boot.efi Mac Only boot loader to run the latest OS X on our otherwise unsupported desktops. Upon the release of OS X 10.10 earlier and through testing, it has become apparent that quite possibly for the very changes you have so eloquently outlined here, that in its present state the current version of this boot.efi will not boot Yosemite.

    As you certainly seem highly advanced and quite capable, a whole community of poor schumks owning old Mac Pro’s hoping to extend the life of there machines a bit longer throughout the public release of OS X 10.10 would be eternally grateful if you would have a “looksie” and perhaps bring the code current enabling it to boot Yosemite. 🙂

  3. Pike,
    As regards the kernel path changes, what about RAID and Fusion helper partitions? Should they still be at root or placed in Apple’s already present directories?
    I notice there is a /System/Library/CoreServices there, so is Apple adding “Kernels to that /System/Library directory?
    Or, may it be in the com.apple.boot.X directory?

    Thanks for all your work!

    • Apple wants people to use: /System/Library/Kernels/kernel for OS X 10.10 and greater, otherwise it will not only confuse people, but it will also break after the first OS upgrade.

  4. Hey Pike

    I was just wondering why grabbing dsdt via terminal no longer working using these 2 commands on Yosemite.

    perl -e ‘open(CMD, “ioreg -lw0 \| grep DSDT|”) or die; while() { chomp; if($_ =~ /\”DSDT\.?\d?\”=]*)>/) { $buff = $1; open(PIP, “|xxd -r -p > ./DSDT.aml”) or die; print PIP “$1”; } }’

    ioreg -arw0 -d1 -c AppleACPIPlatformExpert | xpath /plist/array/dict/dict[2]/data[2]/text\(\) | base64 -D -o ./DSDT.aml

  5. Pike, I managed to use the function to decompress the LZVN compressed kernelcache.


    I have one request:
    You managed to track down the decompression function within kexttools and other software, could you do the same for the 32 bit part of kextcache and also in both the 32 bit as well as 64 bit parts of kextcache look up where the compression function is?

    Thanks a lot in advance 😀

  6. Pingback: LZVN take II | Pike's Universum

  7. Pingback: LZVN take II | Pike's Universum

  8. Pingback: LZVN packed Apple Logo’s | Pike's Universum

  9. Greetings,

    Hi guys. This is a `bit off ‘ the subject of this thread, however, after endless searching for “kernelcache” via google, I reached this post. I think you might be able to help. I’m running mavericks and I built xnu manually as I’ve been doing for years. I’ve installed and have been running the kernel just fine, however, there’s one glaring difference. The stock kernel boots in approximately 6-8 seconds (using kernelcache). This kernel however, takes 30-40 seconds to boot. I’m presuming that the kernel I built is not a `prelinked’ kernel.

    The system is definitely not loading the kernelcache file when I boot with the kernel that I built.

    I’m somewhat new to the concept of prelinked mach_kernels. Do you have any ideas on how to go about getting my self-compiled kernel to boot from the kernelcache file?, or; i.e., is there some other way to get this kernel to use the already existing kernelcache file that the stock kernel uses? Or, is that a bad idea? Does the fact that the kernel I built having a different name such as mach_kernel.new, that I chose, as to not overwrite the stock kernel, possibly have anything to do with this?

    I do, however, understand the basis of what the kernelcache is as well as why it is used, but I have no idea how to use kextcache to achieve what I’m trying to do, and if using that is even necessary in my specific situation. Apple seems somewhat elusive regarding this. I’ve only stumbled upon one webpage that basically is just referencing the man page on kextcache.

    Just as a point of interest, I’m booting this kernel via adding it to nvram boot-args=”Kernel=mach_kernel.new”

    The primary reason that I’m wanting to do this is because I want to rectify the extremely slow boot with this self-compiled kernel. I’ve tried rebuilding the caches, etc… and that does nothing, as far as affecting the speed up.

    Any suggestions would be greatly appreciated.

    • Hi,

      Yup. This is likely the crux of the problem: nvram boot-args=”Kernel=mach_kernel.new”

      With Yosemite you can add boot argument kcsuffix=.new and then the kextd (deamon) will use it when it re-creates the kernel cache, but this doesn’t work with Mavericks so you need to use /usr/sbin/kextcache and make your own pre-linked kernel cache, and add boot argument “Kernel Cache” to make it work.

  10. Hey,

    Thanks for the tip. That’s kinda what I thought, or was thinking at some point. Unfortunately, I’m not that familiar with using kextcache, at least in the way we’re talking about. I’m more of a logician when it comes to imperative subsystems of mach, such as, IPC and VM. As far as the tools go, I’m familiar with otool and nm, but not so much with kextcache. So, basically, the kernel image and all necessary drivers in question here, are being read and loaded off the disk each time thus causing the slow boot. That sucks.

    Do you have any idea what parameters I would need to pass to kextcache to make this work ? And, Wouldn’t that possibly overwrite the stock kernel’s kernelcache file that already exists in the /Startup subdir ?

  11. Hello,

    As I believe I was the first to mention/run by/contact you regarding your assistance with the Mac Pro Yosemite boot loader, I just wanted stop by again and personally express my upmost appreciation for the time and effort you put forth on this project. As I gathered from your blog and mentioned within my post here back in June, I truly admire your highly advanced skills. You certainly possess an exceptional gift. I must say however that what I find most impressive is how freely you share your gift with the world.

    Thanks again !

    • Hi Greg,

      Oh yeah now I remember. You asked me to have a look, but at that time I simply had no time for it. Too busy with other stuff. You know.

      And thank you so much for your kind words. I tell you. Yesterday, after reading and approving your comment, I simply had no words to reply to you. I know it is weird. I mean. Let’s face it. For most people it’s all about the money. Not so for me. Not anymore. It took some time to sink in, but after losing a sister. Someone so smart. So brilliant. Thing is. My parents are divorced, and when she came back home from school to have a chat with me… because dad wasn’t there and mom was working… I was always busy. The big brother she looked up against. But I had no time for her, because I thought that it was all about the money. Now I regret that decision, but that was also an eye opener. I realised that something had to change. And that something was I. Now I don’t care about money anymore, and I try to be a better person. And what you see/read here, is me trying to become that person.

      Thanks again!

  12. Pingback: Recover HD booting with macosxbootloader | Pike's Universum

  13. Pingback: Apple’s kext signing bypassed… | Pike's Universum

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s