I guess so, because Template Haskell is not available on ARM. But yes, then you can write out the lenses manually.
EDIT: And this link ties Template Haskell to GHCi: http://stackoverflow.com/a/10929803
I don't think it's true that Template Haskell isn't available on ARM, at least not with recent versions of GHC.
Maybe what you're thinking of is the problem with cross-compiling and Template Haskell. Generally speaking, that does not work because Template Haskell can do evil platform-specific things at compile time, so if the host and target architectures don't match, you can run into problems.
Anyway, you can use Template Haskell on ARM, you just have to compile it on ARM.
Do you mean Template Haskell? If so, I'm pretty sure it's not required for use, just to have the lenses defined for you. You can still define them manually, at the cost of a little extra boilerplate.
If you actually mean ghci, then I have no idea what you're talking about...