I installed the latest 1.6 firmware and noticed anytime i hit the record button in 120fps it locks up the camera to the point that i have to remove the battery to get it to reset.
After doing the battery pull sometimes it will actually record 120 fps and mostly not.
Is there something i need to do to fix this?
Formatting in camera is usually the best thing to do. Since the card is rated at V90, it should handle the recording without issue.
Do you have a second memory card to try? Perhaps yours developed a fault?
Though it is sounding like it's the firmware at fault. I'm not sure, but can it be downgraded to the prior version? Perhaps a Canon service center could do that?
Beyond that, the only other thing I can think of is if you are now recording in a particularly warm or hot environment?
I would agree with the information that rs-eos was able to provide to you. Please test to see if a different memory card produces the same issue where the camera is unable to record high frame rate video. You may also clear out your settings and restore them back to factory default to see if this helps resolve the issue.
In case the issue persists then the next step is to suggest on sending the camera in to our facility.
Canon U.S.A., Inc. has created a new online repair portal that allows you to set up service in a few simple steps. The repair portal gives you the ability to set up service for multiple pieces of equipment at once, and to receive a repair estimate in the majority of cases, depending on your model and issue. The portal also allows you to upload images or videos that will assist us in repairing your product. You can also select how you wish to be notified of the progress of your repair. The portal's service history section allows you to view all services that have been performed on any of your camera or video products since January 7, 2020.
Please follow the link below to access our online repair portal to arrange for service:
Instructions for Accessing and Using the Online Repair Portal.
You will need to access or create your My Canon Account.
If you already have a My Canon Account and your product is already registered, simply click on the “Get Repair Services” link on the left menu and follow the onscreen instructions to arrange for service for your product.
If you have a My Canon Account and your product is not registered, you must register your product first. Click on the “Get Repair Services” link on the left menu, then click on the “Register Product” link on the right. After your product is registered, click on the “Get Repair Service” link on the left menu and follow the onscreen instructions to arrange for service for your product.
If you do not have a My Canon Account, you will need to create one. After you create your account, click on the “Add Product” link to register your first product. After your product is registered, click on the “Get Repair Service” link on the left menu and follow the onscreen instructions to arrange for service for your product.
Once you have completed the repair request, you will have an opportunity to print a copy of the request for your records. This request form will also contain shipping instructions and an address label that you will attach to the outside of your shipping box when mailing your equipment for repair.
Also check the specs of your memory card and look in the manual to see what sustained write speed you'd need for 120 fps. Don't be fooled by the main number that appears on most cards as that is usually the theoretical max read speed.
The best spec to look at is the "V" rating. e.g. V30, V60, V90. These specify sustained write speeds in megabytes per second. Most manuals then specify recording bitrates in megabits per second, so divide that by 8.
Example: For the EOS C70, one 4K codec at 24 fps is 410 Mbps. Dividing by 8 gives approx 51 MBps. So a V30 card would be no good. A V60 should work, but there are other factors such as generated heat and some equipment will lower speeds to reduce heat. For this particular codec, I rely on V90 rated cards.