Retro USB Firmware Update 0.1.8

Firmware version 0.1.8 is now available from the Retro USB page. This version adds several improvements:


  • Added support for ISO keyboards, commonly used outside the USA. This should fix the key mapping for the ^ or @ key (the key to the left of 1) and the key (the key to the right of the left shift). Mostly untested since I don’t have any ISO keyboards.
  • Keymap type can be cycled between ANSI, ISO, and JIS (currently non-functional) with the new help command Ctrl-Shift-Capslock-T
  • The keymap type is automatically set to ISO at startup if an Apple-brand ISO keyboard is detected (untested). If you have a non-Apple ISO keyboard, you’ll need to switch to ISO manually with Ctrl-Shift-Capslock-T.
  • Single-function USB devices are now prioritized over composite devices. Prevents a mouse with a keyboard macro feature from usurping the role of keyboard.
  • New help command shows the USB vid:pid or ADB handler ID of the keyboard and mouse: Ctrl-Shift-Capslock-I
  • Disabled HID report descriptor parser’s error check for report items with count = 0. Some real USB devices do this, like the Logitech RX 250 mouse.
  • Added 250ms delay at startup in ADB-to-USB mode, before attempting any external communication

If you have an ISO keyboard, and you’ve previously used Retro USB with firmware earlier than 0.1.8 on an OSX Mac, you’ll need to delete the OSX keyboard preferences to make it “forget” Retro USB. Delete the file /Library/Preferences/, then restart. If you don’t do this, your key mappings may be incorrect.


  • Permanently enables USB composite device support
  • Increases mouse speed by 20% in USB-to-ADB mode

Retro USB is an input converter for USB and ADB keyboards and mice. It works in two directions, connecting modern USB peripherals to a classic ADB-based Macintosh or Apple IIgs computer, or ADB peripherals to a USB-based computer running Windows, OSX, or Linux. The foreign keyboards and mice behave exactly like native peripherals, requiring no special software or drivers – just plug it in and go.

This post was originally published on this site.