Howto install macOS El Capitan on a 2009 MacbookPro

I’m trying to sell a 2009 MacbookPro. It’s the model MacbookPro5.5 and Apple supports macOS El Capitan 10.11 as latest available version.

I’ve wiped all data from the installed SSD and had to boot from an external disk. Now I’ve got two problems:

  1. I’ve only got a Mac with Big Sur and Apple Silicon. I cannot use the package installer from the download provided by Apple to create the installer App for El Capitan. However, I need access to the installer so that I’m able to use the createinstallmedia command.
  2. The 2009 MacbookPro is already wiped and has only access to the recovery mode. You cannot execute the package installer in Recovery Mode to extract the media.

Luckily I’ve found this blog post from Chris Warrick who explained how to extract the installer App from the package:

  1. Attach an external Disk which contains the downloaded pkg from Apple. You’ll need enough space on that Disk to extract the pkg and it needs to be writeable
  2. Open the Terminal from inside the Recovery Mode
  3. Go to the mounted volume
  4. Extract the package:
$ pkgutil --expand InstallMacOSX.pkg elcapitan
$ ls -F elcapitan
Distribution*       InstallMacOSX.pkg/ Resources/
$ cd elcapitan/InstallMacOSX.pkg/
$ tar -xvf Payload
x .
x ./Install OS X El
x ./Install OS X El

Now we can try to create the install media from the installer app. Make sure you’ve attach another disk which can be overwritten by the installer. In this example its named “MyBlankUSBDrive”:

# "Install OS X El" --volume /Volumes/MyBlankUSBDrive --applicationpath "Install OS X El"
Install OS X El does not appear to be a valid OS installer application.

The InstallESD.dmg image is missing, which we’ll need to add to the right location:

$ mkdir "Install OS X El"
$ mv InstallESD.dmg "Install OS X El"
# "Install OS X El" --volume /Volumes/MyBlankUSBDrive --applicationpath "Install OS X El"
Ready to start.
To continue we need to erase the disk at /Volumes/MyBlankUSBDrive.
If you wish to continue type (Y) then press return:

Now we’ll have a valid installation medium which can be used to start the installer from. You can reboot from that disk and should be able to install El Capitan.

However, I’ve encountered another annoying issue which caused the installer to fail:

El Capitan Installer cannot be verified

Oh great… On to the next commands you can try from the Terminal inside the Recovery OS:

  1. installer -pkg /Volumes/Mac\ OS\ X\ Install\ DVD/Packages/OSInstall.mpkg -target /Volumes/"XXX" where XXX is the name of the disk you’re installing to.
  2. Wait for the installation to say it’s complete. You will not see any sort of progress display.

Great, you’ve got El Capitan installed! Apple had some issues with certificates and people found a way to either use the above commands for installation or you’ll have to tinker with your Macs time settings so that the signature is valid again. I would have expected that Apple resigned all installers so I wouldn’t have to use these commands at all but doesn’t look like they did.

My Review of the MacBook Pro 13″ (2020) with Apple Silicon


After careful considerations and watching a lot of YouTube videos about the new Macs with Apple Silicon hardware, I’ve decided to order myself a shiny new MacBook Pro 13″ with 16GB RAM and 512GB SSD. I could compare it to my works MacBook Pro 16″ as well as my older MacBook Pro 15″ from mid 2014 and I must say, I’m really impressed.

General Things

The hardware is just great. I like the overall form factor and its small size compared to my wife’s MacBook Air 13″ 2015. The MacBooks internal speaker sound reasonable, but cannot compare to the awesome sound of the MacBook Pro 16″. But since I don’t use the internal speaker that often, I can live with the current quality.

The temperature of the MacBook is always cold, regardless of the current workload. This means, you cannot use it anymore to warm your hands in winter but also its totally quiet, even when it has an internal fan! This is a huge plus, as I’m finally having a quiet desktop again!

Another thing I like is the instant on/wakeup. This machine feels like it is an iPad. That also affects the battery life which is just crazy and unparalleled. If you’ll attach a screen it will turn on immediately. There’s no fade to black first.

M1 compatible apps

Apple Silicon is using arm64 as new architecture compared to Intel. That means all existing Intel Mac Software is run in Rosetta 2, the emulation layer for software which is only compiled for the Intel architecture. There’s already a huge list of supported software. Some apps are not working and even Homebrew has its ongoing issues, but is already useable.

Software left to check at a later time

Docker preview is already available for Apple Silicon, but is not a final stable version.

LuLu Firewall for outgoing connections is currently compiled for the Intel architecture. However, there’s already work going on in that area and I’m looking forward to it.

Visual Studio Code – Insiders available for Apple Silicon, but not a final stable version. Crashes since its last update and I’ve replaced it with the Intel version again.

Thunderbird is still compiled for Intel, whereby Firefox is already available for Apple Silicon.

StarCraft 2 is still compiled for Intel, whereby World of Warcraft is already available for Apple Silicon. Works in FullHD on external screen without sync on low Settings but high texture settings around 60-80 FPS.

Other Software I use but which is still compiled for Intel:

  • TextMate
  • Tunnelblick
  • Jdownloader 2
  • Spotify
  • Logitech Options

Using Safari as new default browser

I’ve read somewhere that Safari is so much faster on Apple Silicon compared to Chrome, so I’ve decided to use Safari as my new default browser for the time being. However, as it turns out, this was only true until Google published an Apple silicon version of Chrome enabling much faster performance.

I’ve upgraded my 1Password license from 6 to 7. This enabled the extension in Safari again, as my previous 1Password 6 license was not supported anymore.

There’s a new webfiltering extension used in Safari > 14. My Adblocker needed  updates to support this. I’m currently using Wipr from the App Store for 1,99$

Wipr’s looking good so far. It filters even most of the YouTube ads, leaving only from time to time a “Skip ad” but without content.

Issues so far

External Screen was not recognized

This is a thing I’ve witnessed on almost all my Macs I’ve used in combination with Thunderbolt docks. I’m using my Macs in Clamshell mode and only rely on wakeup by typing on external keyboard or clicking on my mouse. The Mac did not wake up and I did not have any picture visible on the screen. However, once I’ve opened the MacBook it waked instantly up and detected all external hardware including the screen.

Internal Screen resolution is wrong

The MacBook Pro wakes up after it was connected via USB-C to an external monitor with WQHD resolution. The screen flickers a little bit and the displayed resolution doesn’t fit the screen. Changing the Display options in System Settings doesn’t change this behaviour and the right side of the desktop is invisible as well as the lower part. If I take a screenshot, it will show all details. Looks like this is a Big Sur problem with external wide screens.

Bluetooth connectivity

This seems to be a well known bug. I’ve connected a Magic Trackpad and it keeps on disconnecting, regardless the real distance to the MacBook Pro. You can manually disconnect, but it will try to reconnect, even when it isn’t touched and will show a lot of annoying system notifications.

automount not working after macOS Catalina updates

I’ve recently upgraded to macOS catalina. My automount mount for music media was broken. I fixed it and today it is again not working.

The last change I did was to install the supplemental update for 10.15.7 which seems to overwrite the /etc/auto_master so my /etc/auto_smb wasn’t loaded anymore. Here’s my current working content:

# Automounter master map
+auto_master		# Use directory service
#/net			-hosts		-nobrowse,hidefromfinder,nosuid
/home			auto_home	-nobrowse,hidefromfinder
/Network/Servers	-fstab
/-			-static
/-			auto_smb	-nosuid,noowners

Don’t forget to run

sudo automount -vc

after it you’ve changed the file. Your automount should now work again.

Fix broken automount mounts on macOS Catalina

I’ve moved my iTunes music library content to my NAS. I’m using automount to keep iTunes happy without losing the connection to the files. After upgrading to macOS Catalina, automount did not work as it used to.

Reason is the changed structure in the APFS container. If you have a look at the disk utility, it will show you a system container and a user container. The system contains macOS and is write protected, while the user container contains all your apps, data and so on.

You’ll just have to prepend your existing automount paths with /System/Volumes/Data. Now you’ll just have to run

sudo automount -vc

and the automounts are working again.

I had to change the iTunes settings back to my automount folder, as the upgrade to Catalina reset it to its default location in your users folder.

Fixing Xcode command line tools after upgrade to macOS Catalina 10.15

Today I’ve updated to macOS Catalina 10.15. I’ve tried to setup zsh instead of bash and ran intro troubles with Xcode command line tools.

If I run

xcode-select -p

I’m seeing my previous installation in /Library/Developer/CommandLineTools. However, if I run

xcode-select --install

I’m seeing the installer which tries to fetch the latest Xcode command line tools. However, it always fails with

Unable to Download App. "Xcode" could not be installed. Please try again later.

I don’t intend to install the large Xcode from the appstore. So I’ve tried to delete the existing installation of the command line tools with

sudo rm -rf /Library/Developer

but the problem is still present.

Many people suggest to go to the page and to search manually for the Xcode command line tools. I thought this wouldn’t work, because I’m only seeing the Xcode command line tools for Xcode 12.

However, we’re already at Xcode 12.1, so I thought this is the wrong download and is already outdated. But after I’ve installed the tools from this dmg, its working again and

xcode-select --install
xcode-select: error: command line tools are already installed, use "Software Update" to install updates

shows a suitable error message.

So lessons learned: using the latest major version of the command line tools installer seems to be sufficient.