If your Arch can't boot because of apparently missing efi bootloader when you switch SSD/HDD just pass --removable when reinstalling grub with grub-install. I think this also might be true with Manjaro, but you can do the same.
Fast, secure and up-to-date instance. PrivacyTools provides knowledge and tools to protect your privacy against global mass surveillance.
Matrix Chat: chat.privacytools.io
Support us on OpenCollective, many contributions are tax deductible!