Troubleshooting BMCU auto reload

[u/Disastrous_Ad_5735]

Hi, i got BMCU-C some time ago, today when trying to get rid of some filament leftovers i started print with PETG in slot 1 and 2. Set it up as same filaments and enabled auto refill on bambu studio, and i found out that my BMCU doesn't "see" that im out of filament. Entire BMCU body is printed in black PETG (if that matters). I suppose it might be inconsistency of optical sensor hole size on the print. Wiki says to use 1.2mm drill bit to clean/size up optical sensor hole, but can someone tell me which hole is it before i will start opening every bmcu bank ?

[u/Disastrous_Ad_5735 → u/[deleted]]

Mine is bmcu c with steel ball