DICE believed they fixed an issue with getting the "I am Bad Company" achievement in Bad Company 1. The issue was related to a patch not unlocking in the game regardless if you had the criteria fulfilled or not. DICE thought they had the issue fixed years ago with a patch update, but for many users there was still an issue with it.
DICE's Joe Grant stated over at their official forums:
We are releasing a new server update on the 24th August. We have a few last checks to make but hopefully ["I am Bad Company"] will be fixed once and for all.
With the lion's share of users having shifted over to the amazing Bad Company 2, now would be a good time to pick that old copy of Bad Company 1 out of your closet and finish it off with some good 'ol fashioned boosting. You should also schedule times that work best for me to boost during.
We've got the full list of Battlefield: Bad Company achievements
- check the list for guides to unlocking them.