After updating the source the only change I needed for packaging was:
--- debian/control 2021-02-04 11:03:03.000000000 +0000
+++ debian/control 2021-05-08 10:27:56.638548003 +0000
@@ -13,7 +13,7 @@
Homepage: http://sourceforge.net/projects/gnu-efi/
Package: gnu-efi
-Architecture: any-amd64 any-i386 any-arm64 armhf
+Architecture: any-amd64 any-i386 any-arm64 armhf riscv64
Depends: ${misc:Depends}
Description: Library for developing EFI applications
GNU toolchain for building applications that can run in the environment
