I have a RPi 3B+ on which I installed two OSes via PINN. That worked fine until now.
Recently I tried to configure my bootloader so I am able to chose the correct OS to boot from my TVs remote-control. As I didn´t find any option on the PINN-user-interface to do so a pressed Alt+Ctrl+F4 which should have rebooted the Pi.
However now I get only the rainbow-screen together with the power-symbol in the upper right corner. As I´m using the exact same hardware as all the time before, I can´t imagine the power-supply is low. In particular as I use the official power-supply with 5.1V output. Instead I assume I crashed the PINN in some way.
So I wondered if I can re-install PINN on my SD-card without needing to re-install the OSes. However when I put the card into my Windows-PC I see several drives named boot_rp44 (probably the RetroPies boot-section) and boot (probably the raspians boot-section) together with one drive named RECOVERY and multiple ones that have only a drive-letter which I can´t access at all (wndows asks me to format those drives).