Dual linux system startup selection

I used the fedora system before the dual linux system was started. later I saw the linuxdeepin promotion and decided to install the dual system for comparison. In other words, the localization of linux in China is good, built-in wps and Sogou Pinyin (this is preferred ). But in the past, all the partitions except boot of fedora were installed in one...
The dual-linux system was used before the selection of the fedora system was started. later, we saw the promotion of the linux deepin and decided to install the dual-system for comparison,

In other words, the localization of linux in China is good, and wps and Sogou Pinyin are built in ). However, in the past, all the partitions except boot of fedora were installed in an lvm partition. deepin should not be identified during installation,

As a result, the system directly enters deepin upon startup and cannot select fedora. I was very depressed. later I thought that although the mbr was overwritten by deepin, the list is always loaded in grub. cfg,

Therefore, I copied grub. cfg of fedora to grub. cfg-fedorabackup, and grub. cfg of deepin to grub. cfg-deepinbackup,

To start a system, you only need to replace it in the grub folder of deepin.