How to run grub from grub rescue mode? And Linux from a flash drive?

Question

linux

The hdd is running Linux and Windows at the same time. During an unscheduled check of the disk by Windows, due to a sharp shutdown, the boot area broke and when it is turned on, only grub rescue mode is started (before that, it displays a read error from 0x802). From rescue mode, the partition with Linux installed is simply not visible, possibly broken by Windows. Now the question itself. I have at hand only a non-rooted android with an sd card and the ability to insert it into a laptop. I can't make a bootable flash drive from it. Is it possible to throw grub2 on a flash drive and run it from rescue mode? I also read that it is enough to format the flash drive in fat and drop the Windows installer files onto it, and the flash drive is recognized as bootable. Can you do the same with Linux?

Answer 1

Nothing will happen with just thrown files of the bootloader, in the sense it doesn’t work that way, you need to make the flash drive active via diskpart, or any other application. Try booting from a Live CD with Linux and see if the disk is alive or not.
Only four commands are available in rescue mode: ls, set, unset, insmod
First, you should give the command: ls
It will return, for example, the following: (hd0) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (hd1 ) (hd1,msdos2) (hd1,msdos1)
If issued, then: set prefix=(YOUR LINUS DISK)/boot/grub
set root=(YOUR LINUS DISK)
With these commands we specify to use the disk for further commands.
Check: ls /boot/grub
If issued: insmod ext3 (or 4, or whatever you have there)
insmod normal
normal
then reboot and go into Linux, then restore the Windows bootloader