桌上型電腦安裝 Windows 10 與 ubuntu 20.04 amd64 Desktop 多重開機，但在今天
ubuntu 更新完重開機就無法開機，連grub2多重開機選單也不見了。試著修復grub2，但在用live USB開機進去並在終端機下指令才發現我的分割區 /dev/sdax 都變成了 /dev/loopx。
　　
請教前輩先進們可有解救之法？

ubuntu@ubuntu:~$ sudo fdisk -l
Disk /dev/loop0: 1.98 GiB, 2103640064 bytes, 4108672 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop1: 29.9 MiB, 31334400 bytes, 61200 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop2: 54.98 MiB, 57626624 bytes, 112552 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop3: 255.58 MiB, 267980800 bytes, 523400 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop4: 62.9 MiB, 65105920 bytes, 127160 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop5: 49.8 MiB, 52203520 bytes, 101960 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/sda: 15.11 GiB, 16219373568 bytes, 31678464 sectors
Disk model: Transcend 16GB  
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 0058FA06-3CFE-4074-A2A4-11BFB6D46739

Device     Start      End  Sectors  Size Type
/dev/sda1   2048 31678430 31676383 15.1G Microsoft basic data
ubuntu@ubuntu:~$