Hey @user_160pb7! Thanks for reaching out to us on the Xfinity Forums! I apologize to hear that your upload is currently locked at 40 Mbps upload. Based on the modem model you provided, even though it's capable of higher speeds, it's currently not certified to receive the higher upload speeds at this time. You can see what modems are by having a look at the enhanced speed section of the compatible modem list. (You may have to put your address in for it to show the modems)

Right now, it looks like the following Netgear modems have been certified for the faster upload:

CBR750

CM2050V

CM2500

CM3000