Using pre-El Capitan Disk Utility in Recovery mode

If you do not like to use the new Disk Utility Apple has introduced in OS X 10.11 (El Capitan), and prefer the older version, you will be able to find quite a few articles on the web that tell you how to patch the old program to use it on the new macOS versions.

But when you have to boot into Recovery mode (by holding cmd+R at system startup), you'll be forced to use the new program.

There's a work-around for that, too, though it'll not be perfect: The window controls, such as the red close button, and the toolbar, will be blank. But if you know where to click, or just the commands from the menu, you'll be fine.

Preparation:

• Have the patched Disk Utility (DU) ready on some disk.
• Have a working OS X system available as well. The system, when booting from it, should be able to run the patched DU app (that's needed because DU wants to load some frameworks, and we'll have to make them available when running the Recovery system).
• If the ssytem on your internal disk is currently not available, you'll have to make both available on an externally connected disk.

Once you've started into the Recovery system, use the menu to launch Terminal.app

In Terminal, figure out where your volume(s) with your patched DU and OS X Systems are: Enter:

That will show a lot of lines. It'll look like this (starting at the top):

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *550.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            500.0 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1 (disk image):
   0:      GUID_partition_scheme                        *2.0 TB     disk1
   1:                  Apple_HFS OS X Base System        1.3 TB     disk1s1
/dev/disk2 (disk image):
   ...

Look for all disks that identify as physical. In those you find the partitions (volumes) that contain your DU and System. On a standard setup, that's usually #2 of disk0 (here called Machintosh HD). Note the rightmost name (here: disk0s2).

Now mount that partition by entering:

You should get a reponse saying something like: Volume Macintosh HD on disk0s2 mounted. Now you can access the files on that volume from Terminal.

Next, use the cd command to enter the directory where you've placed DU. If you had placed it into the /Applications folder, and if the volume was named "Macintosh HD" (i.e. the name shown by the previous diskutil mount command), you'd enter:

Now you may try to launch the program by typing its name, following by the path into its executable. In the case of DU, that would be:

But if you press Return, you'll get an error message along the lines of: dyld: Library not loaded: /System/Library/Frameworks/DiscRecordingUI.framework/Versions/A/DiscRecordingUI

To fix that, enter:

Now you can repeat the previous command to launch DU. This time, the will be a few more messages in the Terminal window, with some warnings. Ignore those. Move the Terminal window away, e.g. downwards, and behind it you should see the good old Disk Utility, listing your disks and partitions on the left.

If you want to see the hidden partitions (something you cannot achieve with the new DU for Sierra), enter this command before launching DU:

Or enter this to enable the Debug menu which will also let you make hidden partitions visible: