I have just published release 1.3 of usfxr on its GitHub repository. This is a small update, but it provides some important fixes (especially when publishing on mobile platforms) and adds the option to export your audio as WAV files (similarly to other SFXR ports). I have to thank Michael Bailey and Owen Roberts for their help with bug detection and fixing in this version.
The Asset Store version
should be live some time next week is also available now.