topic 5D MARK lll firmware update not working in EOS DSLR & Mirrorless Cameras

5D MARK lll firmware update not working

kariwright145 — Wed, 18 Jun 2025 23:16:12 GMT

I successfully installed firmware update on my R5 and was attempting to do the same with my 5D Mark lll. However, after trying 2 different formatted sd cards, downloading update to them and installing in camera, it keeps telling me memory card containing firmware is required to update. Can anyone tell me what I need to do? Not sure why same procedure worked just fine with R5 but won't with my 5D. I currently have firmware version 1.2.3 and the latest (or last) version is 1.3.6 Thank you!

Re: 5D MARK lll firmware update not working

jrhoffman75 — Wed, 18 Jun 2025 23:23:04 GMT

Do you have two cards installed? Sometimes that causes a problem; if so try removing the one w/o firmware update.

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 00:18:35 GMT

No, only 1, the sd card that I formatted before downloading update. I tried the one I had been using forever already in my camera, then I tried the sd card that I successfully updated firmware with my R5. Reformatting for 5D first. I've checked and double checked that download was successful and on my sd card.

Re: 5D MARK lll firmware update not working

p4pictures — Thu, 19 Jun 2025 06:30:03 GMT

What is the capacity of the card you are using for the firmware update? If it’s 128GB or larger that might be part of the problem.

Re: 5D MARK lll firmware update not working

shadowsports — Thu, 19 Jun 2025 11:28:47 GMT

Greetings,

We have to ask and ensure the 1.3.6 .FIR (firmware file) was placed in the root directory of the SD card? I assume you did since the R5 Mark II update was successful.

@Brian's recommendation sounds very probable at this point. I've never checked the 5DmkIII's media slot requirements.

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 12:12:31 GMT

1 card was 64GB, the other 128GB. The recommended perimeters. I just used the brand new 128GB I bought just for this on my R5 camera updates. I reformatted in my 5D when trying to do the updates in it. Had my camera set to P mode. All the steps I just did successfully with my R5 after watching several YouTube tutorials.

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 12:20:43 GMT

I selected correct most current up to date Sequoia for Mac. The download is on my as card, just not sure why 5D is not recognizing it. As I previously mentioned, I tried 2 different SD cards. A 64GB, and a 128GB.

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 12:22:32 GMT

Thank you, I triple checked that as well. I did the same steps I had just successfully updated my R5 with. It was the root, not any sub folders.

Re: 5D MARK lll firmware update not working

jrhoffman75 — Thu, 19 Jun 2025 12:24:36 GMT

Is the card slot containing your card selected as the playback slot?

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 12:48:58 GMT

It was set to record to multiple. I hadn’t changed anything as it worked fine with taking photos with just my SD card. My R5 was preset to standard and I only have an SD card I’ve been using in it. Just ordered a CF as a backup. I will try setting it to standard as well unless you suggest something different. Thank you!

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 12:59:40 GMT

According to my search, for firmware updates it shouldn’t matter the camera will read updates regardless of the record settings? According to search of different camera forums.

Re: 5D MARK lll firmware update not working

jrhoffman75 — Thu, 19 Jun 2025 13:02:16 GMT

I don’t know. Just trying to think of what could be wrong. I’ve never run into the problem.

Re: 5D MARK lll firmware update not working

kariwright145 — Thu, 19 Jun 2025 13:45:55 GMT

Thank you for your suggestions!

Re: 5D MARK lll firmware update not working

jrhoffman75 — Thu, 19 Jun 2025 13:51:00 GMT

I will notify a moderator. I know the 5D Mark III is out of support but maybe they can see if the tech folks can assist.

Re: 5D MARK lll firmware update not working

Stephen — Thu, 19 Jun 2025 14:23:39 GMT

Phone support can walk you through any available options, however, if the camera requires any service technician physical intervention by having to send the camera to Canon, we cannot help. Our team is at 1-800-OK-CANON (800-652-2666).

Please also be aware that firmware files are product-specific - you cannot apply a firmware file for the R5 to the 5D Mark III.
You need the file from THIS PAGE
You can download eos5d3-v136-mac.dmg for macOS, or eos5d3-v136-win.zip for Windows.
I've also attached the installation procedures as a PDF for both Windows and macOS so you can reference them.

I hope this helps!

Re: 5D MARK lll firmware update not working

jrhoffman75 — Thu, 19 Jun 2025 14:26:13 GMT

Thanks Stephen. Good to know phone support would be available for Kari.

Re: 5D MARK lll firmware update not working

kariwright145 — Fri, 20 Jun 2025 12:43:02 GMT

Thanks for all your efforts! I reached out on this page due to the notice on Canons website when downloading update (which was specific to the 5D Mark iii), that no support was being provided any longer for it since it had been discontinued a while back. I’ll call the number provided when I have time.