To start with the blinking Question mark is the system looking for the drive to load the OS.
-
So do you have either a mounted drive internally or an externally? Is is running the OS version this system supports. I would use a macOS Sierra (10.12.x) bootable drive as using High Sierra (10.13.x). The highest this system can support (High Sierra) may not work as the systems firmware may not be able to work with the newer APFS file system.
+
So do you have either a mounted drive internally or an externally? Is it running the OS version this system supports. I would use a macOS Sierra (10.12.x) bootable drive as using High Sierra (10.13.x). The highest this system can support (High Sierra) may not work as the systems firmware may not be able to work with the newer APFS file system.
Using the '''Option (⌥)''' key you should be able to select the external drive using the Startup manager.
I’m not sure I understand your TLA MCP term. Its best not to use your own TLA/FLA’s as most people won’t know what you mean technically there is no Multi-Chip Package on this logic board. If you are referring to the CPU or GPU chips just call them out. I’m guessing your CPU is running hot as its stuck in a loop looking for that boot drive.
=== Update (02/24/2021) ===
Ah! You have a mismatch issue! El Capitan is HFS/HFS+ based, High Sierra and newer are APFS based.
-
* Your systems firmware was upgraded during the HS macOS install to support APFS volumes, so its having issues with the older HFS/HFS+ drive.
+
* Your systems firmware was upgraded during the macOS High Sierra install to support APFS volumes, so its having issues with the older HFS/HFS+ drive.
And/Or the SSD you installed is a AHCI/NVMe drive instead of a mSATA which your system requires.
-
* Make sure you are using an mSATA drive. Review this great guide [link|https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
+
* Make sure you are using an mSATA drive internally. Review this great guide [link|https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
To start with the blinking Question mark is the system looking for the drive to load the OS.
So do you have either a mounted drive internally or an externally? Is is running the OS version this system supports. I would use a macOS Sierra (10.12.x) bootable drive as using High Sierra (10.13.x). The highest this system can support (High Sierra) may not work as the systems firmware may not be able to work with the newer APFS file system.
Using the '''Option (⌥)''' key you should be able to select the external drive using the Startup manager.
I’m not sure I understand your TLA MCP term. Its best not to use your own TLA/FLA’s as most people won’t know what you mean technically there is no Multi-Chip Package on this logic board. If you are referring to the CPU or GPU chips just call them out. I’m guessing your CPU is running hot as its stuck in a loop looking for that boot drive.
=== Update (02/24/2021) ===
-
Ah! You have a mismatch issue! El Capitan is HFS/HFS+ based, High Sierra and newer are APFS based. and/or the SSD you installed is a AHCI/NVMe drive instead of a mSATA which your system requires.
+
Ah! You have a mismatch issue! El Capitan is HFS/HFS+ based, High Sierra and newer are APFS based.
-
Your systems firmware was upgraded during the HS macOS install to support APFS volumes, so its having issues with the older HFS/HFS+ drive.
+
* Your systems firmware was upgraded during the HS macOS install to support APFS volumes, so its having issues with the older HFS/HFS+ drive.
+
And/Or the SSD you installed is a AHCI/NVMe drive instead of a mSATA which your system requires.
-
Make sure you are using an mSATA drive. Review this great guide [link|https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
+
* Make sure you are using an mSATA drive. Review this great guide [link|https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
To start with the blinking Question mark is the system looking for the drive to load the OS.
So do you have either a mounted drive internally or an externally? Is is running the OS version this system supports. I would use a macOS Sierra (10.12.x) bootable drive as using High Sierra (10.13.x). The highest this system can support (High Sierra) may not work as the systems firmware may not be able to work with the newer APFS file system.
Using the '''Option (⌥)''' key you should be able to select the external drive using the Startup manager.
I’m not sure I understand your TLA MCP term. Its best not to use your own TLA/FLA’s as most people won’t know what you mean technically there is no Multi-Chip Package on this logic board. If you are referring to the CPU or GPU chips just call them out. I’m guessing your CPU is running hot as its stuck in a loop looking for that boot drive.
+
+
=== Update (02/24/2021) ===
+
Ah! You have a mismatch issue! El Capitan is HFS/HFS+ based, High Sierra and newer are APFS based. and/or the SSD you installed is a AHCI/NVMe drive instead of a mSATA which your system requires.
+
+
Your systems firmware was upgraded during the HS macOS install to support APFS volumes, so its having issues with the older HFS/HFS+ drive.
+
+
Make sure you are using an mSATA drive. Review this great guide [link|https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs]
To start with the blinking Question mark is the system looking for the drive to load the OS.
So do you have either a mounted drive internally or an externally? Is is running the OS version this system supports. I would use a macOS Sierra (10.12.x) bootable drive as using High Sierra (10.13.x). The highest this system can support (High Sierra) may not work as the systems firmware may not be able to work with the newer APFS file system.
Using the '''Option (⌥)''' key you should be able to select the external drive using the Startup manager.
Reference: [https://support.apple.com/en-us/HT201255|Mac startup key combinations]
I’m not sure I understand your TLA MCP term. Its best not to use your own TLA/FLA’s as most people won’t know what you mean technically there is no Multi-Chip Package on this logic board. If you are referring to the CPU or GPU chips just call them out. I’m guessing your CPU is running hot as its stuck in a loop looking for that boot drive.