Hi, I'm having some trouble while recording video on the dji mimo app using the dji om4. Firstly, although I have 10gb of storage space left on my smartphone I'm unable to record video using the rear camera and it's showing that dji mimo can't record since there is no space whereas I am able to record video using the front camera. Secondly the manual mode to control exposure, iso and shutter speed is not showing in both video and photo mode.

Hello there Anurag Roy. I am sorry for the trouble this has caused and thank you for reaching out. May we know what is the model of the mobile device that you are using please for us to be able to isolate the said issue? Thank you.

I'm facing the same issue with Samsung M30 on OSMO 3.

Photo Video Storage Issue

Using a Samsung Galaxy Note20 Ultra with DJI OM 4.

This combination generally works well together for amateur videography. The basic use for many people is for travel and vacation. For instance,  I have a vacation coming up to New Zealand. I intend to use the  S20 Ultra as my primary photo and video device due to size, weight and it does an outstanding job considering it is a smartphone camera. In make sure I had enough memory to capture lots of video and photos for a 3 week trip I installed a 500MB SD card suitable for high resolution photos and video. I set the default camera setting to store images to this SD card. It all works well.
Because I like tech gadgets and thought I just might be able to improve my videography skills a bit, I purchased the OM 4. So far I have been mostly pleased with the features. Then I found out MIMO software saves all video the the camera memory under Phone/DJI/dji.mimo/Camera. My brief research shows no way to change this. On my home tower PC I can easily move files in order to keep phone storage minimal but carrying this PC with me on vacation is not an option. Bottom line is it is pretty obvious MIMO needs a setting to change the default save location. It sounds easy enough but I understand DJI works with dozens of manufactures and languages and all phones are not created equal. In this case, DJI lists the Note20Ultra as being comparable.  This compatibility should include the ability to set the default file storage location.
PS - as a side note I also own a DJI Mavic Air 2 drone. I am looking forward to combining video shot with the MA 2 with video shot with the assistance of the OM 4. I have not taken the time yet to see just what it takes to combine and post edit them together. If your design team has not considered this, it should. At least to the point of using a common interface to keep files in a suitable  location to access for editing.