ATI Radeon HD 4850 on Sierra

[lisman]

Hi,
I have successfully installed Sierra with everything working (including graphics) on legacy bootloader (old GA-P55A- MB).
I also have a Radeon HD4850 with 512 MB mem.
It is detected, but it is detected with 7MB only, and the graphics performance is very bad and laggy.
This is the description from the about this mac -> Overview: "Graphics ATI Radeon HD 4850 Series 7 MB".

I am upgrading from OSX ML. There i used $$$$.kext and it worked perfectly.
(attached are images from sierra and ML).

Any ideas on how to fix this issue?
Thanks!.

My HW:
MB: GA-P55A-UD3 (F11)
CPU: Inter i7 870
RAM: 8 GB.
Graphics: ATI Radeon HD 4850 with 512 MB.

 

[Fl0r!an]

Spoofing the device ID to HD 4870 (-> 0x94401002) should do the trick. Details are in the Radeon Compatibility thread (HD 4xxx generation is missing, but the general procedure still applies).

 

[lisman]

Spoofing the device ID to HD 4870 (-> 0x94401002) should do the trick. Details are in the Radeon Compatibility thread (HD 4xxx generation is missing, but the general procedure still applies).

Works great now.
Thank you.

 

[trypakias]

Spoofing the device ID to HD 4870 (-> 0x94401002) should do the trick. Details are in the Radeon Compatibility thread (HD 4xxx generation is missing, but the general procedure still applies).

Spoofing the ID didn't do the work
I got the device ID (radeon 4850, 0x94421002) and added it to the AMD4800Controller.kext, didn't have to change the ATIRadeonX2000.kext cause it already included the ID... But after restarting, sierra recognises the card but still 5mb... Any other ideas?