If you encounter the message "No software update is available" when trying to boot an Apple Silicon (M-Series) Mac using MacCheck, follow the steps below to troubleshoot.
⚠️ Issue Context
This issue is specific to Apple Silicon (M-Series) Macs and typically indicates that the device is not detecting the proper Base OS to initiate an external boot. It may also suggest system-level corruption.
Step 1: Verify the Base OS on the External Drive
Please make sure your external bootable drive is loaded with the correct Base OS version.
How to Check the Base OS Version:
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Boot the Mac into Recovery Mode:
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Power off the Mac.
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Hold the Power button until you see "Loading startup options."
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Select Options > Continue to enter macOS Recovery.
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Open Disk Utility from the recovery menu.
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In Disk Utility, locate and select the disk image titled "macOS Base System" in the left-hand panel (as shown below):
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Confirm the Base OS version displayed. Compatible versions include:
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macOS 10 (Catalina)
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macOS 11 (Big Sur)
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macOS 12 (Monterey)
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macOS 13 (Ventura)
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macOS 14 (Sonoma)
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macOS 15 (Sequoia)
✅ Ensure the external drive is built using a supported version.
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Step 2: Revive the Mac Firmware (If Step 1 - Doesn’t Resolve the Issue)
If the Mac still does not boot from the external drive after verifying the correct Base OS, the macOS firmware may be corrupted.
Solution: Revive Using Apple Configurator
This type of issue requires a firmware revive using Apple Configurator. There are no alternative troubleshooting steps.
⚠️ This process restores the device’s firmware without erasing data.