Good evening.
For all of you wondering what will happen if your Mini 4 pro is re-classified to C1 and becomes swapped (e.g. service case caused by hardware or software defect).

(Service case handling on DJI's side is not that optimal but have to be discussed separately....
Important here is that you contact DJI via chat (may per phone) to assure that replacement drone comes WITH C1 label - this IS possible!)

I've done exactly this and the replacement unit comes with an accessory package which contains the C1 sticker.

If you have re-linked your new drone to RC you will see that you neither can change the max altitude above 120m nor you can enter e-ID.
BUT: If you click on "remove height constraint" you will be redirected to re-apply for C1 certification.
DO this!

In the upcoming dialogue uncheck "send" and apply for C1 certification.
After applying you are IMMEDIATELY able to upload the "proof" images of the stickers applied to your new drone.
Then you can finish this process with clicking the appropriate button on the bottom of the page.

It takes a while (in my case 2 hours) for final approval by DJI.
You can re-load your certificate (the certificates contains the serial number of your drone (!)) and now you're ready to go!

After next startup of RC and drone you are able to set up altitude to max of 500m and you can enter your e-ID at the bottom of the security page (shown in several threads here).

Nothing of the above is described by DJI - this is result of my own researches and trials with kind support from Swen (THANKS!) out of this forum.

Hope this helps others.

Have a nice evening.
Warm regards,
Ralf

Hi Ralf. Thank you for sharing your experience with re-classifying the DJI Mini 4 Pro to C1 after a replacement. Your detailed process and tips for obtaining C1 certification will certainly be helpful for others facing similar issues. It's great to hear that, with some effort and persistence, you were able to successfully navigate the process of obtaining C1 certification for your replacement unit. 

In addition, we'd like to highlight that the new C1 label pack will be sent with the replaced drone, but you need to stick the label to your new drone and apply for the certificate document again. Sorry for the inconvenience caused. Should you have any requests or further concerns, please let us know, and we'll always be glad to help!