Back in December I picked up a couple Utorch UT01’s from eas. He described them as “These are intact lights with the flakey UT01 driver. They’ve seen a bit of use. These are probably only useful to someone who likes to make tiny drivers.” Well, that was back in Dec 2019 and I made the drivers right away, but kept running into problems. I thought something was buggy with firmware, and I set it aside for 5 months.
Well, I just dusted them off yesterday and finally got it working. As it turns out, I had mis-wired the switch. 
I used the top board from the stock driver, so I could assure proper placement of the switch and it keys into slots in the driver cavity to keep it from spinning. I crafted a new (li-ion only) driver using a linearly controlled FET via a QX7138, run by a attiny412 running RampingIOS (D4V2 UI). I should have thought ahead and used a attiny816 (now that I have Anduril running on the 1-Series) because Anduril is just too big for 4KB. I could use another FSM firmware though, like Baton which will fit easily. Now this is truly an e-switch 14500 light worth using!
PS - oddly enough, everyone seems to have blamed the original issue on the switch being flaky. The switch is the only original thing I’m using and it seems to work perfectly fine for me on drivers that were known to have the “switch” issue. Weird.