Greetings from South Africa!
No matter what I try, I am unable to calibrate the compass on my I2.

I've made sure there is absolutely no metal on me and that I'm very far away from any structure/buildings, etc. I'm filming in the Karoo, which is a semi-desert (a game reserve with open landscape), and keeping in mind (from past experience) that ore/certain rock types interfere with compass calibration, I've been driving up and down over 10km in all directions to try find a place to calibrate, but I keep getting the error "strong electromagnetic interference". Probably by now I've tried over 10 different locations.

I've checked the sensors' status in DJI Go 4, and they've always been green when attemting to calibrate. And yes, my firmware is 100% up to date.

I am able to take off indoors in OPTI (Vision) Mode, and then fly outside - the bird gives absolutely no errors (flies and responds normally to flight inputs too) and smoothly transitions into Green GPS mode, until I land - then it immediately give the 'compass needs to be calibrated' error and won't allow me to take off again.

Here is a bit of backstory - I've flown probably 450+ times with this bird, and have done countless calibrations in the past. One thing I've noticed is that older batteries (150+ cycles) are unable to perform a compass calibration - I always have to use semi-new batteries (is this normal, and is there a fix for this?). My newest pack (pair), now has 77 charge cycles; the one I've been using for attempted calibration here in the Karoo, and I've made sure they are fully charged. I've even cycled it fully again to see if that wouldn't change anything. They are paired to each other.

I know one should calibrate the compass as little as possible, but every time I fly more than about 50km from my previous flight location - the app insists that I calibrate before allowing me to take off (again, is this normal?). I fly all over the country on a weekly basis...

I've been flying here in the Karoo on the exact location plenty over the past year, and have never had issues with calibration.

Is my hardware faulty, or does it sound like a firmware issue? If someone knows of a fix, or cause, I would appreciate it immensely!!! Getting pretty desperate...

Hi DaviidS, my sincere apologies for the inconvenienced. For the Inspire 2 batteries (TB50), discharging the battery level by 80% of the total power is counted as one cycle. The battery’s maximum number of charges covered under warranty is less than 200 cycles and it should be less than 6 months old. May I know if your drone experience crash or any hard landings before? When you calibrate the compass using the old battery, did you receive an error message? If yes, please provide short video or a screenshot of the error message for further checking. You can upload it by using google-drive or Dropbox and provide the link here. Just a reference, if the magnetic-field intensity is more than 30% of Earth magnetic-field intensity, it will seriously affect the drone. The compass calibration is required to calibrate when the indicator light is flashing fast alternating red and yellow. It is suggested to only calibrate the compass when the DJI Go 4 APP or the status indicator prompt you to do so. Make sure you're not carrying ferromagnetic materials with you during calibration process such as phones. Make sure you're not near on a metal objects such as a metal bridge, cars, scaffolding. Please tap on "Reply" so that I can receive a notification from your response. Thank you.