that is correct. the mlc is not needed. you only need the slc from before installing cbhc or just in general in case something happens or the otp.bin, which can decrypt the slc. you can only really fix one issue this way, which is cbhc. the cbhcremover should fix a cbhc brick, so it's good to have the slc if anything else messes up. there's no way to fix anything with the otp.bin unless you know exactly what's wrong with the system. cbhc, as I mentioned, has an app specifically for that.
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another possible "brick" is one with the sys_prod.xml, if you try region hax. the wrong number causes nothing, including the browser, to open. and, if you delete the user or possibly just nnid for the system when you did that, both wii and wii u disc channels disappear. cbhc is the system.xml, so it's a different file.