Fixing rubber battery cover on Sofirn BLF LT1 Lantern

[EBuff75]

There are a number a discussions online about this issue as it's relatively common, but I wanted to add a topic here with my own twist, just in case anyone runs into this issue.  

Last night I used my Sofirn BLF LT1 lantern during a power outage.  The power came back on a few hours later and this morning I charged the lantern back up.  When it was done charging, I made a mistake - I accidentally caught the rubber USB-C charging port cover when I unplugged the cord and pulled the cover off.  No damage, but now I had to figure out how to reinstall it.  And THAT was a problem.

The cover has a rubber "post" that sticks through a hole in the body of the lantern.  In the middle of the post is a bulge (don't bother - all the jokes about this have already been made online in other discussions about this exact topic!) that acts as a retainer.  Once that bulge is pushed through the (much smaller) opening, it acts as a retainer to keep the cover from being pulled off (usually).  But getting that retaining bulge back through the hole is the problem, as the rubber is fairly soft, which doesn't provide a good way to push it through as it just folds / smushes.

Online, I found various suggestions, ranging from freezing the rubber to make it stiffer, open up the lantern to pull it through from the inside (the post extends about 3/16 of an inch past the knob), using rubbing alcohol as a lubricant, using pins/needles/very narrow pliers to force the knob through the opening, etc.

I spent about 30mins trying various suggestions, but still didn't have any luck and was worried that I was going to damage the rubber cover in the process.  What finally worked for me was a combination of the ideas and some creative destruction.

Tools used:

• Mini screwdriver kit
• Needle nose pliers (assorted)
• Iris micro dissection scissors
• Rubbing alcohol
• An extensive vocabulary of expletives

Tools (alcohol and expletives not shown):
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How I did it:

• Unscrew the battery compartment and set aside
• Remove the two screws (I used a 3mm Phillips bit) that hold the control board in place. There is plenty of slack in the wires so that once the screws are out, the board can be pulled up and to the side to get it out of the way, although you may need a pair of sharp tweezers, or a pick, or a very narrow set of needle nose pliers to pull it up enough to grab it.
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• Slightly trim the knob on the retaining post.  I used a set of micro scissors to trim off little pieces of the rubber, but a razor would probably work too.  
• Push the end of the post through the opening in the body of the lantern and then use needle nose pliers (or some good tweezers, or even some forceps) to pull the post through until the retaining knob pops through the opening.  If it still won't fit, trim a bit more. (you can see the trimmed post sticking through at the bottom right)
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• To reinstall the circuit board, line up the USB-C port on it with the opening and push it into place at an angle.  Once the USB-C port is lined up, the board should slide down into place, already lined up for the screws.  
• Reinstall the screws and then the batteries/battery compartment
• Test the light to make sure that it's still working

Back together!
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Just a note that doing it this way will mean that the USB cover won't be as well-retained as it was previously.  On the plus side, this whole process only takes a couple of minutes to do and should be very quick if you need to put it back on sometime in the future.

Hopefully you never need to do this, but if you do, maybe my experience will help!