MBP 1,1-10,2 Intall El Capitan paralell to Catalina?

[HoreaG]

Got a 13" MBP 2009 gifted. Installed El Capitan and upgraded to 8 GB RAM (and in a second step added an SSD). Surpisingly usable. So I became insatiable and bought his younger sibling, the MBP 13" mid 2012, my thought being that it has a superior CPU (i-series vs. dualcore) and I can add more RAM.
After upgrade to 16 GB and installing Catalina I swear it is slower compared to the MBP2009.

So, how do I install El Capitan onto the MBP 2012, given it already has Catalina (with APFS) and Catalina should remain installed, giving a dual boot machine? I have no experience with dual booting on Macs.

 

[Bigwaff]

So, how do I install El Capitan onto the MBP 2012, given it already has Catalina (with APFS) and Catalina should remain installed, giving a dual boot machine? I have no experience with dual booting on Macs.

First, download El Crapitan and create USB media installer.

Create a bootable installer for macOS - Apple Support

You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system. These steps are primarily for system administrators and other experienced users.

support.apple.com

El Crapitan and Crapalina use different file system formats. HFS+ for El Crapitan, APFS for Crapalina. You will need to create a new volume on your MBP 2012 internal storage for El Crapitan. I believe you can only do this while booted from Recovery (press and hold Command+R keys while booting) and using Disk Utility.

Add, delete, or erase APFS volumes in Disk Utility on Mac

In Disk Utility on Mac, add, delete, or erase APFS volumes.

support.apple.com

Don't know what your use case is for being able to boot both, but if El Crapitan is just for goofing, I recommend you install El Crapitan on an external USB drive rather than a separate volume on the internal storage.

Regardless of whether El Crapitan is installed to internal or external storage, press and hold Option while booting to get the boot picker. In the boot picker, pick which macOS version you want to boot with.

 

[HoreaG]

El Crapitan and Crapalina use different file system formats. HFS+ for El Crapitan, APFS for Crapalina. You will need to create a new volume on your MBP 2012 internal storage for El Crapitan. I believe you can only do this while booted from Recovery (press and hold Command+R keys while booting) and using Disk Utility.

Sounds straightforward. My fear was that I somehow need to integrate a HFS+ container into APFS. Now I need to see how to shrink the APFS partitions and make space for HPFS+.

Don't know what your use case is for being able to boot both, but if El Crapitan is just for goofing, I recommend you install El Crapitan on an external USB drive rather than a separate volume on the internal storage.

The plan is to have El Capitan as main working environment and Catalina only ocassionally for what does not work under Capitan. Since FF Dynasty I have almost everything I usually use, so Capitan is enough for me. What I need is a mailclient that can authentificate with the TLS 1.2 or 1.3 as El Capitan does not use these newer versions.

 

[bobesch]

@HoreaG
Your 2009 2cduo 13" MBP can go up to dosdude1/Mojave (last version for 32bit-Aps) and OCLP/Monterey or Ventura (but without Metal-support). Monterey runs decent, Sequioa is a bit struggling and maybe more a proof-of-concept.
I've done that on my late2008 2,4GHz 13"MB Unibody with 8GB RAM, dd1/Mojave + OCLP/Ventura and both run in a decent speed.
(Before that I was quite happy with dosdude1-patched Mojave on my early2008 15" MBP4,1 with 6GB RAM for some time).

Your 2012 i7 dualcore 13" MBP with 16GB RAM is fine with native-Mojave (for 32bit-Apps) and OCLP/Monterey-Sequoia.
My daily driver for on the go is a 2013 i7 11"MBA (8GB RAM / 2TB NVMe) with MultiBoot of native-Mojave / OCLP-Ventura / OCLP-Sequoia and a separate Volume for the plethora of my personal files and backups.

Problem with macOS beyond Mojave is the indexing of media (mainly photographs), which is causing permanent distress for the CPU. That may cause the difference You notice in performance between Your two 13" MBP.
Up to dosdude1-patched or native Mojave (or earlier) You don't have to bother about media-indexing. Beyond you should and switch it of by a terminal command, which isn't necessary for OCLP-patched Macs, since media-analysis is switched of through the OCLP-patching routines anyway. (read more here #125)

If You concider to try out a DualBoot-Machine with Mojave plus OCLP-patched macOS, You better start from the scratch!
The SSD should be erased completely and be reformatted in GIUD/APFS file-system.
With single Container, that holds separate Volumes for
(a) dd1-patched (c2duo) or native (i7) Mojave,
(b) personal files
(c/d/e) OCLP-patched Monterey, Ventura and/or Sequoia

You'll need a 32GB-USB2/3 stick for each version:
- native Mojave (i7)
- dosdude1-patched Mojave (c2duo)
- OCLP-patched Monterey up to Sequioa (a separeta stick for both the c2duo and the i7)

Things can be done in this sequence (done this several times):
1) get the dd1-mojave patcher; download MojaveInstaller through the PatcherApp; Create the USB-Installer
2) start the MojaveInstaller-USB-Stick; erase the internal SSD (GUID/APFS), create separate Volumes for Mojave + PersonnalData + Monterey/Ventura/Sequoia.
3) Install Mojave, only for the c2duo Reboot from the USB-Stick and Patch Mojave through the PostInstall-procedure. (the i7 can run Mojave natively and You don't have to run PostInstall-Patching)
4) Launch Mojave, download/install the OCLP-Patcher.App.
5) download the macOS-installer and create the installer-USB-stick through the OCLP.App
6) Bless the USB-Stick and the SSD with the OC-EFIBoot
7) 2-Step Reboot (hold ALT) from the USB-Stick (1) EFiBoot => (2) Installer
8) Install macOS on the provided Volume and perform Patching.
9) perform step 5-9 for an addition Volume/macOS-version.


You'll have to create the USB-sticks with the Patching-Apps provided from
- dosdude1 (Mojave) or
- OCLP (Monterey up to Sequoia)
since the process of creating the USB-stick will also add specific files mandatory for installing/patching and when it comes to OCLP are specific for each Mac-model !
For more informations thorougly read the how-to's provided from dosdude1 and the OCLP-team.

For the installation of Ventura and beyond on the c2duo 2009 13" MBP You'll need to provide
an USB2-Hub and an external keyboard/mouse,
since Ventura and beyond do not provide drivers for USB1 (mouse and keyboard)
until the system was patched by OCLP.
(Maybe preparing the USB-stick through the OCLP-App may also include a workaround now ...)

So, that's it. No rocket-science.
dosdude1 and the team behind OCLP did a marvellous job to make the installation and patching as easy as possible,
and prevent valuable legacy Macs from beeing doomned.

Feel free to ask questions,
and have fun!

Cheers, @bobesch

 

[HoreaG]

Your 2009 2cduo 13" MBP can go up to dosdude1/Mojave (last version for 32bit-Aps) and OCLP/Monterey or Ventura (but without Metal-support). Monterey runs decent, Sequioa is a bit struggling and maybe more a proof-of-concept.

Thank you for the detailed instructions.
I guess I will remain with up to HS with any of my hardware without metal and Monterey with hw that supports metal just to stay below Catalina. To be honest El Capitan satisfys all my needs, now that we have FF Dynasty and a version of Thunderbird that can handle the authentification methods El Capitan does not natively. Although the concept of containers and shared content between them is appealing. (The only minor problem I still have with El Capitan is that Word 2011 handles footnotes differently to more recent versions.)

I will try out the newer versions of MacOS (jumping over Catalina) on my newly bought (speak about GAS) more powerfull MBPs, these being a 15" MBP 2012 retina I already have (and most probably will smack to the floor one day as it is a wonderfull machine except it has extreme ghosting) and a 15" MBP 2014 that will arrive soon.

Crazy idea, could I install Windows into a container? Guess not, but it is not hurting to ask. Maybe somehow inject APFS drivers to the Windows installation? (Paragon has APFS read/write drivers for Win.)