worked for me
I have been suffering for weeks and lost more hair than usual.
i searched and searched and found this page. THANK YOU FOR POSTING this fix worked for me.
I both changed the USB setting and power-cycles with removing, then reinserting the SIM as suggested.
Immediately my phone got back to "normal" speed like the day before and after my update (I only noticed the slow down a week or two after update)
I truly appreciate the effort that people volunteer to helping solve these gadget bugs (and I run an IT company and I perform QA almost every week; I know how hard it is to find these fixes!)