Hi. It would be nice if you could add base64 from GNU coreutils. Especially including the -d and -w options. It shouldn't need much storage, as bas64 functionality is already included in busybox' uuencode implementation, I guess. I think this would have a big benefit, coreutils is an essential part of nearly every Linux distribution and therefore always installed. uuencode/decode however is often packaged as sharutils and optional. Therefore people tend to use base64.
Fixed in git: http://git.busybox.net/busybox/commit/?id=ee06264a29c81a2d309c9919222d61ff92aa7b7c Will be in 1.18.x