Hello Pirmin,
I admire your courage to resize2fs from the initial GENODE partition to 1 TB as there are many stories from people failing such attempts (with Linux as host system). Therefore, I suggest you use the Linux live system at hand to remove the original tiny GENODE partition, create a new one with the desired size, and create a fresh ext2 file system on it. Don't miss to restore the file contents.
Regards