Support Note  The firmware release notes for USBcan II / USBcan Rugged / PCIcan II / Kvaser Memorator mentions a "slightly revised" hardware and talks about two different CPU versions. Do you have more information on this? Renesas have improved the flash memory technology in their M16C CPUs that are used on the Kvaser devices mentioned above. The new CPUs are not fully compatible with the old ones. The main difference is that the algorithms used to program the flash memory has changed. The old CPUs are known as M306NA or M16C/NA. The new CPUs are known as M306N4 or M16C/N4. Kvaser have started to use the new CPUs in hardware manufactured from February 2006. In order to support the new CPU type, a new firmware is needed. This firmware will of course be programmed into all new hardware at manufacturing time. The new firmware, which has version 2.9, can also be used without restrictions on older hardware. This will also be the case for future versions of the firmware. For technical reasons it is not possible to downgrade the firmware in a device with firmware 2.9 or newer to a firmware with version 2.8 or older.   When you upgrade an old device with firmware 2.8 or older, to firmware 2.9 (or newer), the upgrade software will issue a warning stating that downgrading will not be possible. No changes to the driver routines are needed when upgrading the firmware from version 2.8 to 2.9. If you upgrade from an older version, you might have to upgrade the driver. Please see the release notes for details. No changes to the application software are needed when upgrading to the new firmware.