Help! secure boot is preventing boot of debian, after opensuse update

I have a PC with two operating systems installed, Debian, and Opensuse. Both are installed with Secure Boot. Each has its own grub installation. Normally I boot debian, and if I want to boot opensuse I select UEFI settings from the main menu and select opensuse from there which launches the opensuse grub. Today I booted opensuse, and did an update which included an update to grub. Now I cannot boot debian as it says bad shim or bad signature. Each grub menu has the alternate O.S. on it, but booting debian from the opensuse grub menu did not work either. Should I disable secure boot temporarily? will that allow booting?