OK, moving slightly from your home point should not have any adverse effect since if you are within 20m of your home point RTH will not (or shouldn't) trigger a increase in altitude and return to home flight but simply land within that 20m radius at the point RTH is triggered.
What I find more intriguing is that critical battery level should not invoke a return to home condition but simply cause the aircraft to slowly decend and land (although you can keep the aircraft airborne by pushing up on the throttle).
The very fact that the battery has reached critical means it has insufficient power remaining to make a return to home flight (that's for the first level) and so will make a landing where it is.
I have to agree with the Editor on this.
On more than one occasion (Just when I need to calibrate my batteries by cycling them to the cut-off point, then fully charging them), I run my I1 all the way to the critical level every 8 to 10 flights.
I fly it to drain the majority of the juice, then use the fight simulator to finish it off which is basically what the manual says to do. I always cycle the batteries after every firmware update too just to be sure they are calibrated.
As matter of personal preference, I set my first level battery warning at 35%, then the critical at 10% which is the lowest it will go but I never fly BLOS and rarely over 600'. I usually disable the Smart RTH just because I never fly that far. I also set the geo fence at no more than 900 feet.(depending on the location, sometimes it's much less but never more than that). I figure that 35% battery is way more than enough to fly 600' and I always come back to land very soon after it hits the first level warning. I use 10% as the critical level because I'd rather it not trigger a landing till the last possible minute.
Everytime I reach the critical battery level, it just begins the landing sequence (landing gear already lowered) and have never had it trigger RTH at that point. I always do this with the I1 about 1 foot above the ground. Never had a problem with doing it that way. I only take it to the critical level when I want to cycle and calibrate the batteries as per the user's manual.
Just last week I was filming a creek with several rocks in it that created some really nice rapids (great for stock footage). The path was right beside of the creek so I walked with the I1 up the creek while filming and was at least 100 meters from where I started and from where the Home Point was recorded. I did periodically reset the home point along the way as well as reset it on a takeoff since I had to install a fresh battery about half way, that should have kept it within the 20 meter distance to keep it from triggering RTH and raising it to the RTH altitude.
Both times when the battery reached about 20%, I brought the I1 over to the path, hovered it till it reached critical level, then it triggered auto land and landed right where it was at. I was still able to raise the throttle to slow the descent and land very softly. At other times I've tried flying with the Smart RTH off and it still accepts my stick inputs for obstacle avoidance. I wish I could set the RTH altitude less than 20 meters because those trees over the creek were no more than 15 ft. above the creek. I can't find anyway to disable RTH. Even the minimum flight altitude is 20 meters and can't be turned off (as far as I know).
Oh, ever since I started out with a 700 class electric, single rotor heli with FPV for filming, I've used an earbud to listen to the alarms and the copter. Back then the earbud was plugged into an SD monitor (10 inch Portable TV with an A/V input) instead of an iPad (one thing I miss on the I1 is the audio so I can hear the motors). I use a regular set of earbuds but use just one of them in my left ear. I like it.
Just wondering if you downloaded the txt files after your last FW upgrade to make sure the FW upgrade was successful or not? I'm sure you did but it was worth asking.
If you have the flight record still in your flight records list, maybe you could send that to DJI. You would need to send them the txt file as confirmation that the FW upgrades were successful as well. (I always keep a copy of the results of my FW upgrade txt files just in case).
If the FW upgrades were successful and you still have the flight record, DJI should replace the AC and camera if they determine that it was a defect in the equipment
I haven't had any problems with mine yet (knock on wood). I did notice after 102 flights that the cooling fan for the electronics was making some noise and suddenly rotated slower than it should so I replaced the fan but other than that, it's all been good.
The FW in mine is:
App - V2.8.0
AC - 1.8.01
RC - 1.6.0
Camera - 1.8.01
I wish you the best of luck in resolving this.
Sorry to hear you had that problem!
Regards,
Joe