在最近安装的 Ubuntu 18.04 中，系统安装正常。但是，尝试将系统内核从内核映像 4.15.0-29-generic 升级到 4.15.0-43-generic 时，内核会因未找到根文件系统而崩溃。
[ 0.327121] md: Waiting for all devices to be available before autodetect
[ 0.327823] md: If you don't use raid, use raid=noautodetect
[ 0.328622] md: Autotecting RAID arrays.
[ 0.629322] md: autorun ...
[ 0.330013] md: ... autorun DONE.
[ 0.330722] VFS: Cannot open root device "UUID=<UUID>" or unknown-block(0,0): error -6
[ 0.331434] Please append a correct "root=" boot option; here are the available partitions:
[ 0.332162] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[ 0.332878] CPU: 2 PID: 1 Comm: swapper/0 Not tained 4.15.0-43-generic #46-Ubuntu
[ 0.333599] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme4, BIOS P2.00 06/01/2015
<KERNEL CALL TRACE>
如您所见，尝试从当前 initramfs (4.15.0-43-generic) 中加载文件系统时，未检测到任何磁盘。切换回之前的 initramfs (4.15.0-29-generic) 仍然可以检测和加载根文件系统。
稍后（几次更新）甚至 4.15.0-29-generic initramfs 也找不到根文件系统。
到目前为止，我已经将所有磁盘检查到 SMART，使用更新的 UEFI 固件刷新主板，并对文件系统执行了多次 fsck。此时，GPT 布局看起来不错，没有文件系统错误，SMART 也没有任何磁盘故障或错误。
我发现继续启动系统的唯一方法是从 Ubuntu 18.04 Live CD 中提取 initramfs 模块并重建 4.15.0-29-generic 的原始 initramfs。这个过程至少取得了有限的成功，因为我可以再次启动系统，尽管没有任何额外的模块，例如 nvidia 显示驱动程序。
任何建议，将不胜感激。
编辑
#> blkid
/dev/loop0: TYPE="squashfs"
/dev/loop1: TYPE="squashfs"
/dev/loop2: TYPE="squashfs"
/dev/loop3: TYPE="squashfs"
/dev/loop4: TYPE="squashfs"
/dev/loop5: TYPE="squashfs"
/dev/loop6: TYPE="squashfs"
/dev/sda1: UUID="9238-307A" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="3a8561c9-9af9-4143-a82c-7af3ecd3284c"
/dev/sda2: UUID="94ddd972-a4d8-4317-8a0a-5a4abfdb9d06" TYPE="ext4" PARTUUID="4a29cc34-5be1-4436-b842-fd203f3a522c"
/dev/sda3: UUID="23ec719e-030a-4ee1-9814-067365b10cb5" TYPE="ext4" PARTUUID="27d64a6a-a723-41d0-8b68-2b9d0aec2833"
/dev/sdb1: UUID="26dc83b3-84db-462f-a2de-37399066036d" TYPE="ext4" PARTUUID="d367e4df-01"
#> 猫/etc/fstab
UUID=94ddd972-a4d8-4317-8a0a-5a4abfdb9d06 / ext4 errors=remount-ro 0 1
UUID=23ec719e-030a-4ee1-9814-067365b10cb5 /home ext4 default 0 2
/swapfile none swap sw 0 0
UUID=26dc83b3-84db-462f-a2de-37399066036d <REDACTED>/26dc83b3-84db-462f-a2de-37399066036d ext4 errors=remount-ro 0 2
UUID=9238-307A /boot/efi vfat defaults 0 1
#> ls -la /boot
drwxr-xr-x 5 root root 4096 Jan 16 09:27 .
drwxr-xr-x 24 root root 4096 Dec 22 03:35 ..
-rw-r--r-- 1 root root 1537161 Jul 17 2018 abi-4.15.0-29-generic
-rw-r--r-- 1 root root 1538114 Nov 15 14:01 abi-4.15.0-42-generic
-rw-r--r-- 1 root root 216807 Jul 17 2018 config-4.15.0-29-generic
-rw-r--r-- 1 root root 217018 Nov 15 14:01 config-4.15.0-42-generic
-rw-r--r-- 1 root root 217018 Dec 6 08:52 config-4.15.0-43-generic
drwxr-xr-x 3 root root 4096 Dec 31 1969 efi
drwxr-xr-x 5 root root 4096 Jan 16 20:56 grub
drwxr-xr-x 4 root root 4096 Jan 15 21:00 grub.bak
-rw-r--r-- 1 root root 54526834 Jan 15 22:03 initrd.img-4.15.0-29-generic
-rw-r--r-- 1 root root 65974838 Jan 15 21:30 initrd.img-4.15.0-29-generic.bak
-rw-r--r-- 1 root root 54526834 Jan 16 09:19 initrd.img-4.15.0-29-generic.working
-rw-r--r-- 1 root root 65987219 Jan 15 09:20 initrd.img-4.15.0-42-generic
-rw-r--r-- 1 root root 65987219 Jan 15 21:30 initrd.img-4.15.0-42-generic.bak
-rw-r--r-- 1 root root 66556554 Jan 16 09:27 initrd.img-4.15.0-43-generic
-rw-r--r-- 1 root root 65990605 Jan 15 21:30 initrd.img-4.15.0-43-generic.bak
-rw-r--r-- 1 root root 55494929 Jan 16 09:21 initrd.img-4.15.0-43-generic.working
-rw-r--r-- 1 root root 182704 Jan 28 2016 memtest86+.bin
-rw-r--r-- 1 root root 184380 Jan 28 2016 memtest86+.elf
-rw-r--r-- 1 root root 184840 Jan 28 2016 memtest86+_multiboot.bin
-rw-r--r-- 1 root root 0 Jul 17 2018 retpoline-4.15.0-29-generic
-rw-r--r-- 1 root root 0 Nov 15 14:01 retpoline-4.15.0-42-generic
-rw------- 1 root root 4040379 Jul 17 2018 System.map-4.15.0-29-generic
-rw------- 1 root root 4048025 Nov 15 14:01 System.map-4.15.0-42-generic
-rw------- 1 root root 4048162 Dec 6 08:52 System.map-4.15.0-43-generic
-rw-r--r-- 1 root root 8257272 Jul 24 23:33 vmlinuz-4.15.0-29-generic
-rw------- 1 root root 8277752 Nov 15 14:04 vmlinuz-4.15.0-42-generic
-rw------- 1 root root 8281848 Dec 6 08:56 vmlinuz-4.15.0-43-generic
-rw------- 1 root root 8281848 Jan 16 09:21 vmlinuz-4.15.0-43-generic.working