I don’t think so and have never heard that, but I could be wrong.

You can just do for f in * (or other shell glob), unless you need find’s fancy search/filtering features.

The shell glob isn’t just simpler, but also more robust, because it works also when the filename contains a newline; find .. | while read -r will crap out on that. Also apparently you want while IFS= read -r because otherwise read might trim whitespace.

If you want to avoid that problem with the newline and still use find, you can use find -exec or find -print0 .. | xargs -0, or find -print0 .. | while IFS= read -r -d ''. I think -print0 is not standard POSIX though.

My built-in SD card reader shows up in lspci as an “SD Host Controller”. Since lspci and lsusb should list everything that’s connected, it should show up there. If it’s not there, it is not connected, or idk, it’s broken maybe. Or it’s not listed with a name, just a number. I think the names come from some database of known devices. Maybe your SD card reader is a unicorn and nobody has ever seen it before and so it’s not in the database.

Pretty sure the main difference is that one puts stuff in a directory called esp (which I assume is a placeholder for the actual directory?), and the other one is put in /efi. That needs to be the path to your efi partition, because that’s where the UEFI expects to find things it can boot. The target is probably redundant, i.e. it defaults to x84_64-efi on Gentoo (maybe not on Arch?) and the id is just a name, you can put whatever there. See man grub-install.