The same advice still stands but even more so if your board is not UEFI ....
Booting Clover in non UEFI mode from the EFI Partition is slightly unusual but not un-heard of , I do it with my Sony Laptop - it's sort of a Hybrid boot mode .. the BIOS boots the boot-loader stub from from the root of the EFI Partition, You can tell if you installed Clover in this mode if there is a 'boot' file in the root of your EFI partition :-
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As I said this is a special case and usualy needs to be supported by a special flag in your BIOS, On my Sony's H2O BIOS the option is called 'Boot EFI first'.
By installing Clover on the EFI partition but booting in legacy mode you could be complicating things for yourself, check to see if you have a /EFI folder in the
root of your
OS X Startup drive, if there is and it has a Clover sub folder then the chances are that your system is booting from there and not from the EFI Partition.
Copy your edited config from /EFI/EFI/Clover to /
OS X Startup drive/EFI/Clover - or re edit it, if this turns out to be the case then i would delete everything from your EFI partition or reformat it from the command line.
Please note that this issue is really off topic, as its a Clover issue not iMessage, if you continue to have Clover problems you should post your questions in to the appropriate thread.
Cheers
Jay