Grub does not detect windows 10 efi boot files

I recently installed lubuntu on new partition, and in doing so, I formatted the efi partition to FAT32. Now I want to boot into Windows 10, but none of the usual recovery methods have worked for me - the efi files are in the efi partition, but nothing seems to recognize them. I can enter the grub menu, so the BIOS boot order is correct. I have tried:

• theupdate-grub command: it doesn't detect the Windows bootloader. Neither does os-prober.
• boot-repair utility: it says that it completed successfully, but it still doesn't work. Here is its bootinfo summary.
• Creating a custom grub entry as described here. It's unable to find the boot files.

I put the boot files into the efi partition by running bootrec and bootsect, and mounting and unmounting the efi partition from a command line in the recovery USB. The recovery files are old - I think they're from Windows 10, but a much older build than the one installed on the drive. Is that what's causing the boot files to not be detected? I don't know what else it could be, since boot-repair finds the efi files in the correct partition (sdb2).

Any help would be much appreciated.