High Sierra MacBook Air Early 2015: Troubleshooting Bootable Cloning Issues

As an Apple Certified tech, I've encountered a peculiar issue while attempting to clone my MacBook Air early 2015's original SSD to a new MemoryX SSD using Carbon Copy Clone. Despite successfully cloning the drive in recovery mode, I'm unable to select the cloned disk as a startup option or boot from it using the Startup Manager.

To provide some background information, my Mac shipped with macOS High Sierra (10.10) and has since been upgraded to later versions. The original SSD started failing, so I backed up the data and its backup boots just fine. This suggests that the issue lies not in the cloning process itself but rather in the MacBook Air's firmware preventing the new SSD from being recognized as a bootable disk.

I've tried connecting the drive while in recovery mode using an OWC USB-SATA case, as one certified tech suggested. The clone appears successful until I attempt to select Apple menu -> System Preferences -> Startup Disk or use the Startup Manager to boot off it. Unfortunately, this route is not yielding the desired results.

In a surprising twist, I am able to boot from an external hard drive and even format the internal drive using Disk Utility on both macOS High Sierra (10.13) and Mojave (10.14). This tells me that the issue isn't related to hardware problems with how I inserted the SSD.

As an Apple Certified tech, I've worked with various Mac models over the years, but this particular problem has left me stumped. It seems that the MacBook Air early 2015 has some sort of firmware restriction preventing it from recognizing the new MemoryX SSD as a bootable disk, despite its supposed compatibility.

If anyone else has encountered a similar issue or has any insights on how to resolve this problem, I'd love to hear your suggestions and work together to find a solution.

High sierra macbook air early 2015