It’s nonsense… using a voltage over x2 the rated voltage of the cell does not magically “wake up” an over discharged cell. I’ll explain what’s actually happening, (on a well designed Li-ion battery) your 4.2V (max) cell is low (likely in UVP state), you connect you 9V battery to it, the voltage on your 9V is likely pulled low due the current draw of your patient battery, voltage on your patient climbs and gets ever closer to 4.2V, at which point OVP kicks on the small protection PCB and will effectively disconnects your 9V battery.
There is two main issues here with this method (again this assumes that the patient battery is actually decent quality and has the protection I talked about) 1: Protection circuitry speed in “disconnecting” your 9V source to the cell and 2: you are not regulating current to your patient battery.
Now Let’s looks at another scenario, the patient battery your charging does not have OVP, and yes, they exist and there are plenty of genuine iphone batteries and nintendo batteries on eBay like this (which look identical to the genuine) some might have simpler protection pre-cell, some might just have diode and a fuse. Anyway, in this scenatio, the voltage on your battery would climb to 4.2V and then… it will keep climbing, 5, 6, 7, BOOM!
In either cases, charging in an unregulated manner like this is dangerous, relying on the last line of defense (protection circuitry, if even present at all) is dangerous. If you want, try doing this with an electrorlytic capacitor, which while it doesn’t t use same chemistry, is very similar construction and the failure mode is incredibly similar, take a 5V rated cap and stick 10V on it, let it draw whatever current it wants (which is what your doing) and see how many seconds it takes before it blows up in your face.
Your conflating things here, which makes me think you truly don’t understand and I’d imagine is the reason your using the “trick” in the first place. Current is not really the primary issue here.
To safely charge an over discharged Li-ion/Li-po battery, all you have to do is limit voltage so it does not surpass the max voltage of the cell (4.2V in this case) and ideally initially limit current and trickle charge up to specified point… all of which a 1 quid 5V USB to Li-ion/Li-po battery charging PCB will do for you automatically (understand, your “trick” isn’t a trick, it’s dumb 
it’s just doing what a dedicated charger is doing but in the most dangerous way possible essentially)
All the info you want is here in the below topic / thread 
I really would just be going over the exact same stuff bud here, like a broken record 
Trouble is because you’ve replaced IC’s and reflown things (randomly) you’ve muddied the waters, you’ll have to tell me also how you conducted your replacements too (step by step) just so I can be sure they aren’t going to cause issues (assuming the measurments your going to take from thaty topic as reference, are in the realms of ok)