If your MacBook freezes or restarts every time you try to update macOS, the problem may be more serious than a normal failed software update.
That is exactly what happened to my MacBook.
Every time I tried to install a macOS update, the MacBook would freeze, restart, and display the message:
“Your computer was restarted because of a problem.”
After investigating the crash reports, I discovered that my Mac was experiencing a SEP Panic. Eventually, I was able to fix the problem by putting the MacBook into DFU mode and performing a Revive using Apple Configurator and another Mac.
After completing the DFU Revive, I tried the macOS update again — and this time it completed successfully.
In this guide, I’ll show you the process I used.
Important: This article describes what worked on my MacBook. A DFU operation deals with low-level firmware and recovery components. Make sure you understand the difference between Revive and Restore before proceeding. A Restore can erase your Mac.
Here’s a video with all the details:
Symptoms: MacBook Freezes or Restarts During an Update
My MacBook worked normally for most everyday tasks. The major problem appeared when I tried to update macOS.
The process would begin, but eventually the Mac would freeze or restart unexpectedly.
After rebooting, macOS displayed the familiar warning:
“Your computer was restarted because of a problem.”
Looking at the panic report revealed references to a SEP Panic.
If you’re experiencing something similar — especially repeated crashes during macOS installation or updates — a firmware Revive may be worth investigating.
This procedure may also be relevant in certain situations where a Mac starts to a black screen with an exclamation mark and requires firmware recovery.
What Is a DFU Revive on a Mac?
DFU stands for Device Firmware Update.
Instead of reinstalling macOS normally from the affected Mac, DFU allows another compatible Mac to communicate with it and repair/update its firmware and recovery components.
For my setup, I used:
The MacBook with the problem
A Mac mini as the host computer
A USB-C to USB-C data cable
Apple Configurator installed on the Mac mini
Another compatible MacBook can also be used as the host instead of a Mac mini.
The important point is that Revive and Restore are not the same thing.
I specifically used Revive Device because my objective was to repair the firmware without intentionally erasing the Mac.
Step 1: Connect the Two Macs
Connect the affected MacBook directly to the host Mac using an appropriate USB-C cable.
Make sure you’re using a cable capable of data transmission, not a cable designed only for charging.
In my case, I actually tested my USB-C cable with a cable tester and verified that both data and power were available.
Also pay attention to which USB-C port is required for DFU on your particular Mac model. The correct DFU port can vary depending on the Mac.
I connected my MacBook directly to the Mac mini rather than running the DFU connection through a hub or dock.
Keep the host Mac connected to power during the procedure as well.
Step 2: Install Apple Configurator
On the host Mac, open the App Store and search for:
Apple Configurator
Install and launch it.
Apple Configurator is where the affected MacBook should appear once you’ve successfully placed it into DFU mode.
Step 3: Put the MacBook Into DFU Mode
This was probably the most frustrating part of the entire process for me.
The MacBook needs to be completely turned off while remaining connected to the host Mac.
For my MacBook, I used the required combination involving the:
Control + Option + Shift + Power button
The timing is important.
I had to try the sequence several times before it worked. So if you don’t get DFU on the first attempt, don’t immediately assume that your Mac or cable is defective.
When I finally got it right, DFU appeared inside Apple Configurator, while the affected MacBook itself remained on a black screen.
That’s the result you’re looking for.
If Apple Configurator displays the Mac normally or you see a padlock instead of DFU, you haven’t successfully entered DFU mode yet.
Because the exact DFU key sequence and port can depend on the Mac model, I recommend checking Apple’s current instructions for your specific model rather than assuming that my exact combination applies to every Mac.
Step 4: Choose “Revive Device”
Once Apple Configurator showed DFU, I right-clicked the device and selected:
Advanced → Revive Device
Apple Configurator then began the Revive process.
At this point, don’t disconnect the USB-C cable or interrupt either computer.
Configurator works through several stages while downloading, preparing, and transferring the required software to the affected Mac.
Eventually, I reached Step 4 — Reviving Device, and the Apple logo appeared on my MacBook.
Important: Make Sure the Host Mac Has Plenty of Free Space
This caused another major problem during my repair.
My first attempts failed because the host Mac didn’t have enough available storage for Apple Configurator to complete the process.
I had to delete applications and unnecessary files to create substantially more free space. In the end, I had around 50 GB available before successfully completing the procedure.
So if Apple Configurator gives you a “No space left on device” error, don’t automatically assume that the MacBook you’re repairing is the problem.
Check the available storage on the host Mac.
In my case, failed attempts also consumed significant temporary storage, so freeing enough space became an important part of getting the Revive to complete.
I would not treat 50 GB as an official universal requirement; it’s simply approximately how much free space I had when my successful attempt was performed.
Step 5: Complete the Revive
Near the end of the process, my MacBook prompted me to select my user account and enter my password.
After authentication succeeded, I selected Restart.
The MacBook restarted normally.
Most importantly, my files and user account were still there.
At that point, the Revive itself was complete.
But I still needed to answer the most important question:
Did it actually fix the original update problem?
Step 6: Try the macOS Update Again
After booting the MacBook normally, I disconnected the DFU cable and opened:
System Settings → Software Update
An update was available, so I started the upgrade again.
Previously, this was where the MacBook would eventually freeze or restart.
This time, it didn’t.
The update downloaded and proceeded normally without the previous freezing behavior.
And ultimately, the macOS update completed successfully.
That was the confirmation I was looking for: after the DFU Revive, the MacBook could finally perform the macOS update that had repeatedly failed before.
What Finally Worked for Me
There were a few lessons from this repair that could save you some time.
First, getting into DFU mode can be tricky. I had to try the button sequence multiple times before Apple Configurator finally displayed DFU.
Second, use a proper USB-C cable that supports data. Trying another known-good cable can eliminate one variable if DFU isn’t appearing.
Third, make sure the host Mac has plenty of free storage before starting. I ultimately had around 50 GB available when the successful Revive was performed.
And finally, if you’re trying to preserve your existing installation, pay very close attention to Revive versus Restore. They are not interchangeable operations.
Did DFU Revive Fix My SEP Panic?
In my case, the result was very encouraging.
Before the Revive, attempts to update macOS repeatedly resulted in freezing/restarting and the panic reports showed a SEP Panic.
After performing the DFU Revive, the Mac booted normally and I was able to perform the macOS update successfully.
So DFU Revive solved the update problem I was experiencing.
That doesn’t necessarily mean every SEP Panic is caused by firmware corruption or that DFU Revive will repair every Mac with similar symptoms. A recurring panic can potentially have other causes, including hardware problems.
But if your Mac still boots and you’re experiencing repeated update failures associated with firmware-related errors, a DFU Revive is an important troubleshooting option to know about.
Watch the Complete DFU Revive Process
I recorded the entire repair, including putting the MacBook into DFU mode, using Apple Configurator, performing the Revive, and testing the macOS update afterward.
If your MacBook is freezing, restarting during macOS updates, showing SEP Panic errors, or you’re having trouble getting Apple Configurator to recognize DFU mode, the video shows what the process looked like on my actual Mac.
Final Thoughts
What initially looked like it could be a serious MacBook hardware failure turned into a successful repair using DFU mode and Apple Configurator Revive.
The key steps were getting the MacBook correctly into DFU mode, using a reliable USB-C data cable, having enough free storage on the host Mac, and choosing Revive Device rather than Restore.
After the Revive completed, my MacBook booted normally and — most importantly — macOS finally updated without freezing or restarting.
If you’re experiencing the same problem, I hope documenting what worked for me saves you some of the trial and error I went through.
