Chosen Solution
I upgraded my A1502 with a NVMe/PCIe SSD (version without adapter which fits directly). was working fine had some sleep/wake failures sometimes so I read through some forums and tried some pmset adjustments in terminal After auso nvram enable-legacy-orom-behavior=1, nothing worked anymore. SMC/NVRAM reset does not seem to do anythingBooting from old original SSD with Catalina which was working perfect does not workEntering safe mode/recovery mode does not workCompletely removing SSD and only starting from catalina usbdrive doesnt work I get no chime nothing, just flashing question mark folder after a while. Is my logic board fried or whats up?
Give this a try How to select a different startup disk. You’ll need an external bootable drive to use. You should also be able to see the drives via the Startup manager pressing the Option key when you restart your system. Reference: Mac startup key combinations
I believe the EFI is damaged. You need to visit an apple store to check whether it can be fixed.
I had the same issue. 2 days spent on it. The MacBook Pro started with black screen, no chime, no Apple logo. After some time it displayed the ? folder. I tried all the options, but no success, I eventually succeed by doing the NVRAM reset buttons (cmd-opt-R-P) for ALMOST 5 minutes and suddenly heard the chime (I press few time the power button to make sure the system started and continued to press the other 4 buttons). To conclude, I now have Catalina on my MacBook Pro retina 13’ early 2015 128GB! I’ve upgraded to a Samsung 970 EVO SSD. However, I learned the hard way that it must be via macOS Mojave. You MUST have a bootable Mojave disk and once the system restart, you should erase the Samsung 970 EVO to reformat it and only then you can restore from backup. Hope it helps! BTW: Since the was issue was with Catalina I moved back to my original SSD.
