That was my original thought too, but its been mentioned that the threaded section is too short to contact the driver by a few people. If that is not the case, this is the most ideal solution IMO
At least on my light, I have continuity. Verified with a multimeter
Hello Dear friends,
Sorry for the delay, now we give a solution for S42 problems：
After Verified by the manufacturer,the length of the tube is too short and it can’t compatible with most length of 18350 and 16340 protection cells and button top cell, the manufacturer adjusted the tube length and they verified the 40 mm tube will solve the problem and allow most cells to be used without the danger to damage it, including the 18350 and 16340 cells. At the same time, they also modified the design of the USB silicone cover.
Any problems, please contact our CS, we will send you a free 40mm tube and USB silicone cover, you can replace it yourself. Please send E-mail to cservice@banggood.com, don’t forget to include your order number, thank you.
By the way.S42 and s42s will use 40 mm tube and the latest USB silicone cover. The s42 now has been sent back to the factory repair, thank you for your understanding and support, we will try our best to do well in the after-sales service.
Best Regards,
Banggood Flashlights Team
Thank you for answering in this thread.
If the light is already on its way, should we wait with contacting CS until it has arrived or contact immediately?
In my case, it has been shipped on the 13th, and if I understand correctly this means that it will not have the new 40mm tube.
Glad to see Banggood coming up with a solution. :+1:
Thanks for resolving this in a great way!
E-mail to Customer Service sent.
Yeah, i love extra LEGO parts. 
Email sent, thank you!
I too sent my email. I wonder how long it will be for these replacements to arrive.
I sent the email, and as expected, they were clueless of this problem and asked me to send videos... 
I hope that is not what will be required for getting the proper parts for this light…
They say they are making a 40mm tube as a solution, do you know how long the original tube is?
Mine was 36.92 mm, but my S41 was 37.22 mm, so figure about 37 mm. Adding 3 mm, then flat tops should fit pretty good. My 18650 BLF A6 tube still won't work right - I added a washer in the tailcap after using it in the reverse position.
Of course this doesn't address the driver issues - not the best UI, poor efficiency even though it says "High efficiency constant current circuit". From maukka's test result here: https://budgetlightforum.com/t/-/45615/148, it sure doesn't behave like a high efficient constant current driver.
I still think the best resolution for this would be redesign the driver and UI, fix the battery issue while retaining tube compatibility with the other lights, and fix the USB cover, and mail out the revised light to all that got this faulty light.
The one and only time I had to deal with their customer service ended with me being so frustrated with their cluelessness that I just ended it before I lost my $#!T on them. $40 in lights that wont be used.
Its really a shame, because there are 3 or 4 other Astrolux lights I really want. But this light, and the OL a01 really make me question if spending money on the SC. SS and S41S is even logical
Got mine today. As expected the 18650 tube, supposedly designed for the S42, did not work.
It doesnt sound like CS is even aware of the problems with the light much less the 18650 tube fit.
Im concerned about compressing and damaging both 18350 & 18650 batts
Im not looking forward to trying to straightening this out……
Edit: Flatop Panasonic worked………. I apologize if my original post mislead anyone
Just received my copy an hour ago. I found a potential fix for the cell length problem. I believe the tail spring could have been engineered better. I removed the tail spring and, using two pairs of needle nose pliers, cut the leg off of the small diameter and simply wound the spring tighter. Now, instead of the coils “stacking” on top of each other, they collapse inside each other. The whole height of the spring now almost completely collapses into the recess in the tailcap. My estimate is a gain of @1.5mm. My Efest purples fit a lot better now. Can’t take photos as I’m at work. Hope this helps!
Oh, that’s unfortunate…
I ordered the 2 18650 tubes Banggood sells for the S42 after first reading about the problem, the aluminum and steel versions, in order to have a workaround.
If they don’t work, I threw good money after bad .
Got mine today, haven’t risked trying the short tube, but the 18650 tube works no problem.
It could have done with a thermal stepdown on turbo!
Hmmm………… what kind of battery…. flatop/protected? Just wondering…… thanks
It was a flat top 30Q.
LG HG2 did not work with blf a6 tube, works ok with S41