I have not been able to resolve this problem.
After an update from windows 10 the computer boots straight in to windows 10.
Originaly I had windows 10 and manjaro kde.
Both systmes are in the same ssd
a different hard drive containing the swap partition and storage area for windows.
There are two small separate partitions for boot(200mb & 500mb) I dont know if the 500mb was ever used because it is empty, the 200mb has some efi files from manjaro.
I tried mounting the partition and re-generation a grub but it said no uefi on this system.
I know it works because the uefi grub menu was working fine before the windows update.
I tried to follow the "Recover grub after windows update" Manjaro instructions but it mixes bios and uefi instruction and I could not make it work.
I dont know why both boot partitions show vfat.
I would really appreciate your help.