MacBook Pro 2014 won’t boot after macOS Big Sur install

shashwath210 wrote:

I did a full reset of the mac using a USB installer for recovery. However, the mac now reboots showing openshell.efi and reset NVRAM.

How did you create the USB installer? It seems like you may have used a third party utility. Who knows if there are any negative side effects with it. Can you boot into the online Big Sur installer through Internet Recovery Mode using Command + Option + R? If so, then make sure to erase the whole physical SSD as GUID partition & APFS (top option). Within Disk Utility you will need to click "View" and select "Show All Devices" before the physical SSD appears on the left pane of Disk Utility.

If you can only boot to the online installer for Mavericks, then you will need to instead partition & format the whole physical drive using the instructions in the following article:

https://eshop.macsales.com/tech_center/formatting/Mac_Formatting_6-10_R3.pdf

You can try running the Apple Diagnostics to see if any hardware issues are detected. Only a failing diagnostic result is useful.

Make sure to disconnect all external devices from the laptop just in case one of them is causing a problem.

FYI, those performance issues & crashes you experienced before upgrading to Big Sur should have been addressed before attempting to upgrade to Big Sur. OS upgrades will almost always complicate things. OS update patches are fine, but not upgrades to a new major version. Having access to those Kernel Panic logs would have been very useful, but they are now gone. Keep in mind the issues you had before the upgrade may be the same reason you are having trouble now to reinstall macOS.

I would start again. Boot into recovery, select disk utilities, erase the drive (top line) then select reinstall the OS. Looks like your first attempt had an error.

How to reinstall macOS - Apple Support

That Mac originally shipped with OS X 10.9.4 (Mavericks). Mavericks predates APFS, and also may have problems accessing https sites and the App Store, which may complicate recovery.

If you do the type of Internet Recovery that reinstalls the original operating system, that might not work unless the internal SSD is formatted using Mac OS Extended (journaled, non-case-senstive) (HFS+). Big Sur is going to want to be installed on an APFS volume. I believe the High Sierra installer will convert an internal SSD from HFS+ to APFS during installation, but I'm not sure about later installers. So if you start recovery with anything earlier than High Sierra, you might need to do an intermediate upgrade to High Sierra before upgrading to Big Sur.

shashwath210 wrote:

I did a full reset of the mac using a USB installer for recovery. However, the mac now reboots showing openshell.efi and reset NVRAM.

HWTech is correct. You should not be seeing those icons. That USB installer is no good; don't use it. The only way to create a "bootable USB installer" is to follow Apple's instructions, which I won't reference here because it will just be distraction you don't need.

How to reinstall macOS - Apple Support explains the various startup key combinations.

Use this one:

• If you used Option-Command-R to start up from Internet Recovery, you might get the latest macOS that is compatible with your Mac.

Erase the startup disk first (obviously).