Socket for screw removal on Koss HV/1LC

[mibag6]

I need to remove one driver on my Koss HV/1LC phones to repair a broken lead. Driver works fine but is intermittent and needs fixin'. What type of socket or nut driver will work to remove the screws that hold the driver in place? A regular socket doesn't fit in the recess around the screw head.
TIA

 

[darrelb]

a 4mm socket should work

 

[mibag6]

Socket is a no go but I used a precision needle nose and was able to remove the bolts. Fortunately, they weren't very tight and came loose pretty easily.
Any ideas on what to use for scrim cloth? I found this thread but I'm not exactly sure what he's using for replacement.
https://audiokarma.org/forums/index.php?threads/koss-hv-1lc-restoration.569420/#post-7487370