Can I upgrade my iMac late 2012 with Broadcom BCM94360CD Wi-Fi/Bluetooth card that supports the 802.11ac?

It's very unlikely.

Other than RAM and if you are very, very brave your hard drive, your iMac is not upgradable. 😟

Tonight I successfully upgraded my late 2012 iMac with the mentioned 802.11ac card following iFixit guides. The original card was glued to the main board with a grey porous glue in addition to the two Torx5 screws. I have a 802.11ac Time Capsule and a 100Mbit internet connection and I got faster speeds wirelessly than before:)

I also upgraded the HDD to a 6G SSD and found an empty SSD card connector on the main board where it should be unpopulated. Happy with my decision to go ahead and disassemble the iMac. I agree you have to be brave to do it but it´s not very difficult.

There is nothing in the iMac that can be changed by the user except for the memory in the 27". Anything else you do voids the warranty and ALL future support from Apple. Apple will never help with your iMac if you change anythng inside.

Good point. I should have mentioned that.

All though, in many many countries, the warranty only lasts for one year.

I started with a physically abused but functional iMac.

It is fine to do with your computer as you wish...and if you get one that has been abused and you have the ability to make t workable again, more power to you.

For the vast majority of users, however, the point has to be understood that if you open the machine you have relinuised all future help from Apple. It doesn't matter if the warranty has expired...if something else goes wrong and you take it to Apple, they will not even accept payment for support of any kind. Once you violate the sanctity of the computer you are entirely on your own.

In your case, you sound like you have the skill set to take care of yourself...so it really doesn't make much difference.

Congratulations on making your Mac a workng computer.

Runnsen, can I ask what fixit guides you used? did you use a software package to test the speeds?

EMC 2544 break down at iFixit is helpful.

I didn´t need to use any software to see the speeds because I both could download at much higher speeds from my 100MBit internet connection and copy data faster wirelessly to and from my Apple Time Capsule hard drive.

Recently I upgraded the CPU to a i7 3.1GHz 3770S, and that too was an easy job following iFixit guides. The iMac doesn´t like to be tampered with repeatedly but now there´s nothing more I can upgrade:)

Beware one cannot upgrade to just any CPU, it has to be one that has the same or lower thermal requirement from the heat sink.

Again, as some people have mentioned, this is all pretty bold warranty breaking stuff:)

Can I just add that the recovery system does not seem to have the correct driver for the WiFi card so if you plan on doing a internet recovery it will need to be via ethernet. I just carried the imac upstairs and connected it with cable and it was ok. The reason I needed recovery was because I sat the iMac up with two SSD drives in Raid0 and then managed to use up all the space. I was not able to get the imac going again until I reinstalled osx and restored from backup.

thank you. do you recall how much it cost for the processor and the wifi card?

I bought both on Ebay. CPU I bought for 259$ including international shipping from Israel. Wifi Card I paid 40$ for with free China post shipping. Worth mentioning I live in Norway:) I was able to sell the i5 2.7GHz cpu from this iMac for 150$ over here. Also worth mentioning: I have spent so much on upgrades and the new screen that I could just as weel have bought a 2013 iMac. All good fun though!

"if you open the machine you have relinuised all future help from Apple. It doesn't matter if the warranty has expired...if something else goes wrong and you take it to Apple, they will not even accept payment for support of any kind."

I'm sorry Ralph, that's just not so. I replace the HDD in my out of warranty iMac. Some months later I began having video problems. I took the iMac to my local Apple Store where they diagnosed the problem and fixed it. It was a bad logic board. I was upfront about replacing the HDD, the tech who worked on my machine said I had done a good job.

I bought on Ebay BCM94360CD for my iMac Late 2012. Wi-Fi is excellent, but no Bluetooth.

Runnsen,is your BCM94360CD working well?

Working well under OSX Mavericks. Not so well under Windows, I can´t find a driver. Maybe I didn´t look hard enough.

In some cases Apple has refused warranty on an iMac that the user has serviced themselves. But typically they will honor the warranty (and in many countries are legally bound to do so) unless they have reason to believe that the service done by the user (or an unauthorized shop) or the replacement part has caused the problem for which warranty service is being requested.

In your case, it was obvious that a replacement hard drive wouldn't cause a problem with the logic board, but that's not always so clear and hence the warranty is at risk of be voided. For most users it's usually best to avoid self-service if the user wants to preserve the warranty. This is particularly true with the current and previous model of iMac which are glued together, not assembled with screws, and hence very difficult for the average user to service, at least not without causing damage.

Regards.