MacOS Catalina: Unable to boot rEFInd after reboot

[Ved Vod]

I have tried both the manual and refind-install installation methods, and they have resulted in the same problem: when I restart my computer in order to access rEFInd, it tries to boot up rEFInd, but fails and boots into recoveryOS, stating that MacOS needs to be redownloaded on the disk
How can I properly boot into rEFInd? I have installed on the EFI of the single MacOS hard drive.

[Roderick W. Smith]

I have several suggestions, which are not mutually exclusive:
Try experimenting with rEFInd on a USB flash drive. That should enable you to try different versions of rEFInd, adjust the configuration, etc., without risking your ability to boot your computer normally.
You might try rEFInd version 0.11.5; this report suggests that some Mac users are having problems with the latest version 0.12.0, but it's not clear why this is.
Try builds made with both GNU-EFI and Tianocore EDK2. Both types of builds are available on the rEFInd downloads page. (The USB flash drive version is built with Tianocore, but you can swap out the rEFInd binary [EFI/BOOT/bootx64.efi] with a GNU-EFI build -- note that the rEFInd binary is generally called EFI/refind/refind_x64.efi, but it's EFI/BOOT/bootx64.efi on the USB flash drive.)
If your Mac is new, you may need to deal with Secure Boot. There are at least two ways to do this:
* You can try disabling Secure Boot, as described on this Apple documentation page.
* Alternatively, you could install Shim and set up a MOK, as described in the rEFInd documentation. I don't have a Mac with Secure Boot, and I'm not even 100% certain that what Apple calls Secure Boot is the same thing as Secure Boot on UEFI-based PCs, so I don't know if this procedure would work; but it might.
Try installing rEFInd in Linux or using the self-install method (if you can get rEFInd to start from a USB flash drive). This is not what I'd try first; I think it's probably safer to experiment with the USB flash drive rather than to try installing to your hard disk from Linux; but if you can get rEFInd to work from a USB flash drive or in some other way, installing from an OS other than macOS might* help.