Wubi - boot recovery after kernel update

The note can be useful to those who are just acquainted with Linux and / or installed it through Wubi under Windows.
Literally today I ran into a problem after updating my Ubuntu kernel - Grub stubbornly did not want to boot the system with the new kernel and sent me to its own boot console, without even offering to choose the boot method from the menu. Googling found that this problem occurs in almost all owners of Ubunt installed via Wubi.

Having rummaged some time in the internet, I found a way to boot Linux with the old kernel from the console is coarse:
> insmod ntfs
> set root=(hd0,1) # , ls
> loopback loop0 /ubuntu/disks/root.disk
> set root=(loop0)
> linux /boot/vmlinuz-2.6.31-14-generic root=/dev/sda1 loop=/ubuntu/disks/root.disk ro #
> initrd /boot/initrd.img-2.6.31-14-generic #
> boot

Everything, the system was loaded. Now, to save yourself from doing these actions, go to the terminal and run sudo update-grub . Now it will be rude to show us a menu with a choice of boot options, and we will be offered to boot with both the new kernel (I had version 2.6.31.19) and the old one (I have 2.6.31.14).
Alas, my 19th kernel still refused to boot (and the new version of the kernel after updating to Wubi-installations doesn’t work for very few), but you could safely use the 14th. But you want to have a normal system with all the updates.
Go google further. On viewing the 100,500th comment in the hundredth bugtracker we find the solution to the problem.
In fact, the problem in the bootloader does not manifest itself during a clean installation of Ubunt (not through Wubi) and it is connected with the operation of the Wubi and Grub loader (Grub, if I understood correctly, cannot read files outside the first 4 GB of the partition).
To correct this annoying misunderstanding, download the wubildr file from here and put it in the root of the disk on which we have Wubi installed (don’t forget to backup our wubildr just in case, you can do it all from Windows). Now rude will ask us to choose the method of loading. Feel free to click on the latest version of the kernel and enjoy.

Ideally, it would still be worth reinstalling Ubuntu to your partition so as not to encounter such problems, and the system does not work as fast on NTFS as it could. But if for some reason there is no way to make a clean installation or you just need to restore the files from the personal directories of Linux users, you can simply restore the download in this way, the benefit takes literally 5 minutes.