How to install GRUB2 on a flash drive?

Question

linux

The laptop hard disk (500 GB) is divided into several partitions using mbr:
the first partition contains the mbr itself;
on the second partition there is a disk C of Windows 8.1;
the third partition stores user data;
the rest of the empty space (let's call it the Remainder) ~ 60 GB is allocated for Linux (the distribution kit is not important).
I want to achieve the following:
Win8.1 and Linux live on the laptop at the same time. Windows and mbr sections remain untouched. To boot Linux, you need to insert a USB flash drive and choose to boot from it. After loading grub'a select Linux or Windows. As I understand it, in order not to occupy the entire flash drive under grub, it is divided into 2 sections. The first partition remains for files in NTFS or FAT32. Grub itself is installed on the second partition of the flash drive.
I tried to do this, but I didn’t succeed, I get an error (sdc2 is the second partition of my flash drive)

grub-install /dev/sdc2
grub-install: предупреждение: Файловая система «ext2» не поддерживает встраивание.
grub-install: ошибка: встраивание невозможно, но оно необходимо для междисковой установки.

Answer 1

The bootloader is placed not in the partition, but in the MBR, it makes no sense to indicate the partition number.