Just bought V20 H990ds . I had the same problem with a 32GB card not being seen. I also had and 8GB card that it saw but said it was corrupt. It said tapped format but when you did the screen would show 20% and then disappear and never format. Both cards were fine on other machines. I found the solution on XDA forums. Remove Sim, start phone with SD card only. Or put sim in slot two start up. It should see the SD card . Put the SIM card back in and you should still be able to see your SD card. What was interesting was that I ejected the 32GB SD card and ones left the SIM card in the original slot 1. I installed the 8GB card that the phone had originally stated was corrupt. This time the card, with the SIM, was immediately recognized and said ready to use. I formatted the card anyway and it formatted fine. It's almost like this phone model required the SD slot to be Sim free the first time and then it was somehow activated. I have a 64GB card on order and we'll see if it plays nice out of the box with exfat
A) Try a different card. Some cards electrically degrade for certain devices. Even if your card works in your PC, it may no longer work in your phone. B) Try the card in another phone. Doesn't have to be the exact same model, but perhaps someone else's LG phone.
