And here it is: charging and killing an YMIR without cover or squadmates' powers (or even squadmates shooting at it). I used the save I had with Kasumi again, but in theory it can be repeated with any other YMIR mech you encounter.
Vanguard vs YMIRI've positioned Kasumi way back at the beginning of the barricades so she doesn't shoot the YMIR. You can see the fight starts with 100% full shields for both.
The strategy is as follows:
1) You have to begin the fight when the YMIR is about half-way done with shooting its machine gun. Sooner than this or later than this will get you killed since you'll either be forced to use a medigel and it won't recharge when you need it, or you'll die cause you'll be under fire by the YMIR's machine gun for too long.
2) Using a medi-gel too soon or too early will get you killed so you have to get the timing right. I use it a few moments before I see my shields break. You have to let the medigel restore your shields as the YMIR is shooting at you. Any point where the medigel is working and the YMIR doesn't shoot its machine gun at you means that you're not using the medigel's restorative abilities to their full potential. You'll go through at least 4 medigels during the fight so I recommend having 4 as minimum.
3) The fight cannot be won without the Unity upgrade that restores shields. Or at least I haven't figured out a way how to do it on my own. I suspect that 2 more squadmates who have warp or reave will allow you chew through the armor faster and it might be possible even with charge alone.
Any comments/questions are welcome