Upgrading 'original' ME to 'C'

We’ve found that we have a mix of MEs - some (including our JTAG parts) are the ‘original’. And new ones will be ‘C’ type.
Since we only have a few of the ‘original’ MEs in the field, I would if possible like to re-flash our stock of ‘original’ parts so that they work the same as the ‘C’ - will simplify long-term support. Is there a way to do this?