However, these changes made the machine incompatible with most Spectrum machine-code software, which is to say virtually all commercial titles; less than 10% would run successfully. In an attempt to remedy this, many TS users built a cartridge with a Spectrum ROM for emulation. The emulation was sufficiently accurate that it was able to run the majority of software produced for the Spectrum. Later, Timex of Portugal produced a Spectrum emulator cartridge that would auto-boot. This cartridge did not fit in a TS2068 as it was higher than TC2068 cartridges. The TC2068 casing was changed to accommodate this.