How to make a custom macOS Recovery (i.e. with custom apps)?

[izzy0242mr]

Does anyone know of a way to do this? I've googled and not found anything helpful.

I have seen a handful of custom recovery partitions (usually for Hackintosh prebuilt installers or modified macOS installers). I'm mostly curious about putting a file browser on a recovery partition so I can boot up and have access to files through a GUI interface rather than Terminal. Linux live discs often can't write (and sometimes can't read) HFS/AFPS formats.

 

[Bigwaff]

Have tried using file URI in Safari?
Ex. file://Volumes/………..

By “access to files”, what do you mean? Even if you had a GUI file browser like Finder in Recovery, you wouldn’t be able to double-click files to launch applications.

 

[!!!]

Just install macOS onto an external drive and install the utilities you want. The problem with the recovery partition is that it doesn't always include the necessary frameworks to run everything.

 

[izzy0242mr]

Just install macOS onto an external drive and install the utilities you want. The problem with the recovery partition is that it doesn't always include the necessary frameworks to run everything.

I want something ultra portable, like a USB flash drive that I can carry on a keychain. In my experience, macOS on a USB drive is a super slow experience.

 

[izzy0242mr]

Have tried using file URI in Safari?
Ex. file://Volumes/………..

By “access to files”, what do you mean? Even if you had a GUI file browser like Finder in Recovery, you wouldn’t be able to double-click files to launch applications.

Hmm…I haven't tried that.

"Access to files" - I mean literally just a file browser that lets me at minimum browse a file directory, and ideally read/write. Basically Finder. Totally fine if I didn't have the ability to launch apps—obviously apps aren't going to work in Recovery mode unless they're specifically set up to do so. But if I could, for example, boot into Recovery, and then browse files with Finder on the internal hard drive (imagine a situation where the Mac crashes and won't boot up and you need to recover files before wiping the disk).

 

[Bigwaff]

"Access to files" - I mean literally just a file browser that lets me at minimum browse a file directory, and ideally read/write.

To “read/write”, you would need to launch application(s) by double-clicking on a file, yes? Otherwise, what purpose would a file browser serve?

 

[izzy0242mr]

To “read/write”, you would need to launch application(s) by double-clicking on a file, yes? Otherwise, what purpose would a file browser serve?

No, I don't want to launch applications. I never said that, and not sure why you are getting stuck on that. Finder can "read" many types of files by default by letting you view them in the Quick Look feature that is part of Finder. That isn't opening an application. "Write" means the ability to modify the files in some way. Making a new folder is "writing" to a disk. Replacing a file with a newer version is also "writing" to the disk. Read/write.

As for "what purpose would a file browser serve," as I said above, "imagine a situation where the Mac crashes and won't boot up and you need to recover files before wiping the disk." That's a pretty basic, standard kind of situation where having file access would be very helpful.

There are also more advanced reasons—perhaps there's a system file that was modified in some way, and if you can pull that file off the drive, copy it off the machine and edit it, and then put it back on the system, you could replace a damaged file.

 

[Bigwaff]

No, I don't want to launch applications. I never said that, and not sure why you are getting stuck on that. Finder can "read" many types of files by default by letting you view them in the Quick Look feature that is part of Finder. That isn't opening an application.

Fair enough. I happen to know how QuickLook works under the covers and how QL plugins typically get installed — when applications get installed. Hence, my focus on applications.

"Write" means the ability to modify the files in some way. Making a new folder is "writing" to a disk. Replacing a file with a newer version is also "writing" to the disk. Read/write.

How you going to modify a file or create a new version of it in Finder? QL doesn’t edit or create files. I assume you wouldn’t use CLI programs in Terminal to “write”. Would somewhat defeat the purpose, yes? Again, my focus on launching applications.

Apologies if my replies come across as too critical. Please take them in the spirit of “consider this” as you ponder the idea of Finder’s usefulness in Recovery.

 

[gilby101]

I have seen a handful of custom recovery partitions (usually for Hackintosh prebuilt installers or modified macOS installers).

That sort of thing works fine for Intel Macs (pre-T2), but Mx Macs (and T2 intel) have much tighter security.

For what sort of Mac are you wanting this?

In what situations would you use this? Remember that Mx Macs essentially have "firmware" on boot disk, without that you won't be able to boot any disk.

I want something ultra portable, like a USB flash drive that I can carry on a keychain.

Easy for a pre-T2 Intel. Anything more recent, it just isn't an option unless you have configured the security on each Mac to allow booting from the USB drive (I think the specific USB drive).

"Access to files" - I mean literally just a file browser that lets me at minimum browse a file directory, and ideally read/write. Basically Finder.

To browse or read, use Finder on another Mac to read the TM (or other) backup disk of the problematic Mac.

"imagine a situation where the Mac crashes and won't boot up and you need to recover files before wiping the disk."

Start in safe mode. If it won't do that, reinstall macOS and hope the data volume is not corrupt.

If the data volume is corrupt you will likely not be able to read any files. In that case, wipe the disk, re-instal macOS and recovery from backup. If the boot and recovery is corrupt: restore in DFU mode and then reinstall macOS and recover from backup.

Read this https://eclecticlight.co/2025/12/09/create-a-bootable-external-disk-for-apple-silicon-macs-in-tahoe/ from Howard Oakley about preparing an external boot disk on Mx Mac.

What it boils down to is that recent macOS and Mx hardware is designed to stop what you are trying to do. The Mac needs to able to boot to recovery and then you can boot from an external macOS disk previously prepared on the Mac.

Wanting an "ultra portable, like a USB flash drive that I can carry on a keychain" make you sound like a receiver of stolen Macs. I am sure you are not, but you are up against protections put in place to discourage theft of Macs and/or their data.

 

[izzy0242mr]

Fair enough. I happen to know how QuickLook works under the covers and how QL plugins typically get installed — when applications get installed. Hence, my focus on applications.

How you going to modify a file or create a new version of it in Finder? QL doesn’t edit or create files. I assume you wouldn’t use CLI programs in Terminal to “write”. Would somewhat defeat the purpose, yes? Again, my focus on launching applications.

Apologies if my replies come across as too critical. Please take them in the spirit of “consider this” as you ponder the idea of Finder’s usefulness in Recovery.

All good. I've run into situations on very old Macs, including Hackintoshes, where sometimes (a) it's useful to add/delete whole files from system root directories (kexts and the like), or (b) where I need to extract documents from a computer and it's not worth it/a pain/difficult/not possible to boot into the OS and I'd have to erase the drive to be able to boot.

Linux works for (b) because some distros let you read HFS+ files, but it is not a good solution for (a) as it does not easily let you modify HFS+ partitions. While I'll mostly just need to READ files from a drive, it would be nice to be able to WRITE too.

I'd be satisfied with the ability to run a file browser in macOS/Mac OS X Recovery that lets me copy/paste and delete files from a hard drive.

 

[izzy0242mr]

That sort of thing works fine for Intel Macs (pre-T2), but Mx Macs (and T2 intel) have much tighter security.

For what sort of Mac are you wanting this?

In what situations would you use this? Remember that Mx Macs essentially have "firmware" on boot disk, without that you won't be able to boot any disk.


Easy for a pre-T2 Intel. Anything more recent, it just isn't an option unless you have configured the security on each Mac to allow booting from the USB drive (I think the specific USB drive).


To browse or read, use Finder on another Mac to read the TM (or other) backup disk of the problematic Mac.


Start in safe mode. If it won't do that, reinstall macOS and hope the data volume is not corrupt.

If the data volume is corrupt you will likely not be able to read any files. In that case, wipe the disk, re-instal macOS and recovery from backup. If the boot and recovery is corrupt: restore in DFU mode and then reinstall macOS and recover from backup.

Read this https://eclecticlight.co/2025/12/09/create-a-bootable-external-disk-for-apple-silicon-macs-in-tahoe/ from Howard Oakley about preparing an external boot disk on Mx Mac.

What it boils down to is that recent macOS and Mx hardware is designed to stop what you are trying to do. The Mac needs to able to boot to recovery and then you can boot from an external macOS disk previously prepared on the Mac.

Wanting an "ultra portable, like a USB flash drive that I can carry on a keychain" make you sound like a receiver of stolen Macs. I am sure you are not, but you are up against protections put in place to discourage theft of Macs and/or their data.

Don't care about AS. I only care about pre-T1/T2 Intel Macs. I don't want to use Target Disk Mode for this; I'd like to be able to access any files on any non-Apple Silicon/T1/T2 Mac from Recovery, full stop.

Safe mode isn't a solution and doesn't always work (think a macOS Tahoe OCLP install that someone shouldn't have done).

"Do a backup." Not the solution and not the issue here. I back up my own devices; but I also work with a number of folks who do not, and encounter friends and family member as the "resident tech person" who had Mac problems and need this kind of thing.

I want a USB drive I can carry around and use to boot into Recovery and access files. That's what I want.

I don't "receive" stolen Macs. As I said, I fix up and repair Macs for friends and family, and I also buy old Macs (legitimately) online that are broken/for parts, fix them up, and flip them as a hobby.

FWIW it's really annoying having to explain your life story and defend every question you have on forums like these. I generally like MacRumors but it's these kinds of unhelpful responses that really ignore what you're asking that turn me off from them.

 

[macaddiict]

I want a USB drive I can carry around and use to boot into Recovery and access files. That's what I want.

What is stopping you from making an external USB boot disk? (just install macOS on a compatible USB drive, using the downloaded macOS nstaller from the App Store)

Before you can use this drive to boot a specific Mac, you must Boot into Recovery and Go to Utilities > Startup Security Utility and set it to "Reduced Security" or "Allow booting from external media" -- if you don't care about T1/T2/M* devices, you're good to go.

Most USB flash drives use very cheap components, which might be why you say it was slow in your past experience. It is tolerable to use macOS from a USB 3.x boot drive as long as you have a good drive designed for this. Still, USB 3.x is always going to be way slower than even a SATA SSD due to the signaling used for USB and the processing overhead.

I've had no issues using the command line in Recovery Mode for the things you're talking about. More recent Recovery Mode has the "Share Drive" utility, too.