Just install the one you want , that will overwrite it.
Beat ya Dark
is there a way to uninstall rev19? because after i installed rev19, i couldn't be able to load up my HD with 2 of my USB loaders : USB Loader GX 2.0 and Coverfloader.
My god, man --- never, ever uninstall an IOS below 200 --- never. Just wanted to make this clear (yes, I realize you said IOS 249 --- but better to be safe than sorry in making assumptions, LOL).
then guys, which rev should i use to overwrite which is suitable for my situation right now.
Our guides generally go with Rev 17 (certain situations like FAT32 USB HD and that would not work; either a higher revision or Hermes IOS 222/223 would work; also Black Ops doesn't like Rev 17, but it likes Hermes or higher Revs of Wani's 249).
Personally I'm only using 21 right now. I have it installed from 249-253 using different bases. I haven't encountered any problems yet. But I don't know what you are into with your Wii and certain revs work better for certain things. Or you can install multiple revs into different slots.
so your saying that any rev will make my USB loader GX 2.0 load up my HD?