[Bug 2140442] Re: cp: cannot stat '/boot/firmware/current/cmdline.txt': No such file or directory

Dave Jones 2140442 at bugs.launchpad.net
Thu Feb 5 18:40:29 UTC 2026 

> This is my full /proc/cmdline:
>
> coherent_pool=1M 8250.nr_uarts=1 snd_bcm2835.enable_headphones=0 cgroup_disable=memory numa_policy=interleave bcm2708_fb.fbwidth=1920 bcm2708_fb.fbheight=1080 bcm2708_fb.fbswap=1 smsc95xx.macaddr=DC:A6:32:6B:96:DB vc_mem.mem_base=0x3ec00000 vc_mem.mem_size=0x40000000 net.ifnames=0 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=LABEL=writable rootfstype=ext4 elevator=deadline rootwait fixrtc vc4.force_hotplug=0x01

On the subject of the kernel command line: most of what you find in
/proc/cmdline is added automatically by the bootloader (and thus
shouldn't be included in the fixed portion stored in cmdline.txt,
because the bootloader may wish to alter it based on circumstances).

Specifically, the following items are definitely added implicitly and
should not appear in cmdline.txt:

coherent_pool=1M
8250.nr_uarts=1
snd_bcm2835.enable_headphones=0
cgroup_disable=memory
numa_policy=interleave
bcm2708_fb.fbwidth=1920
bcm2708_fb.fbheight=1080
bcm2708_fb.fbswap=1
smsc95xx.macaddr=DC:A6:32:6B:96:DB
vc_mem.mem_base=0x3ec00000
vc_mem.mem_size=0x40000000

Then there's the rest:

net.ifnames=0
dwc_otg.lpm_enable=0
console=ttyAMA0,115200
console=tty1
root=LABEL=writable
rootfstype=ext4
elevator=deadline
rootwait
fixrtc
vc4.force_hotplug=0x01

Of these:

* net.ifnames=0 is something from a long time ago (I'm guessing this
system has been upgraded several times) that used to be used to force
things like eth0 to be eth0 (rather than the huge MAC-based string on
the older Pi models). Nowadays, netplan configuration handles that
instead so it can be excluded.

* dwc_otg.lpm_enable=0 is still in our present cmdline.txt but I suspect
it's no longer needed; we use dwc2 these days so I *think* this is a no-
op but there's no harm in leaving it

* console=ttyAMA0,115200 needs to be in there for the serial console,
but it should actually be console=serial0,115200 in the cmdline.txt --
the bootloader re-writes "serial0" to the actual serial port which in
turn depends on "other" configuration (the serial port used on the GPIO
header can change depending on the device-tree)

* console=tty1 needs to be there if you want a console on your video
output

* All the root=, rootfstype=, and rootwait stuff needs to be there

* fixrtc is required as the Pi (typically) doesn't have an RTC (actually
the Pi 5 does but it lacks a battery unless one is installed manually)

* vc4.force_hotplug=0x01 should only be required if you have issues with
the Pi detecting your monitor at boot time. Still, the fact it's there
suggests you have had such issues at some point in the past?

So, in current/cmdline.txt I would recommend something like:

console=serial0,115200 multipath=off dwc_otg.lpm_enable=0 console=tty1
root=LABEL=writable rootfstype=ext4 panic=10 rootwait fixrtc
vc4.force_hotplug=0x01

In other words, the default, plus the vc4.force_hotplug=0x01 work-
around. The multipath=off item was added to prevent multipathd running
all the time and eating memory (important on the smaller Pis), and
panic=10 to enable automatic fallback in the case of kernel failure.

And on that subject...

> And what's shit about rebooting twice (last line above)? :)

That's flash-kernel warning about the new A/B boot implementation.
There's a brief note about this in the questing release notes [1] which
has some links with more information (the original blog post [2] has all
the gory details but is a rather long read). In brief: to make the Pi
"test" new boot assets a reboot is required; the "tryboot" mode can only
be entered by reboot, not from cold boot. Hence when booting with
untested assets in place, a new service will force a reboot into the
"tryboot" mode.

Given you're on a Pi 4, one thing I would strongly recommend checking
before rebooting: run "sudo rpi-eeprom-update" and make sure the
"CURRENT" date reported is greater than or equal to 2022-11-25. If you
have an earlier EEPROM date, it must be upgraded before questing's boot
system will work.

Unfortunately, while I put that in questing's release notes I didn't
think to add a u-r-u quirk to guard against it. That's on the roadmap
for resolute, and I'm hoping to get to it shortly.

Anyway, hope that answers most of the questions!

[1]: https://discourse.ubuntu.com/t/questing-quokka-release-
notes/59220#p-151948-raspberry-pi-67

[2]: https://waldorf.waveform.org.uk/2025/pull-yourself-up-by-your-
bootstraps.html

-- 
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https://bugs.launchpad.net/bugs/2140442

Title:
  cp: cannot stat '/boot/firmware/current/cmdline.txt': No such file or
  directory

Status in flash-kernel package in Ubuntu:
  New

Bug description:
  This interrupted a release upgrade from plucky to questing on my pi4.
  After dropping to a shell, "apt -f install" yields the same error, as
  does just calling "flash-kernel":

  root at pi4:~# apt -f install
  The following packages were automatically installed and are no longer required:
    g++-14                     libboost-iostreams1.83.0        libclang-cpp18          libllvm19            libxml2                          linux-raspi-tools-6.14.0-1018
    g++-14-aarch64-linux-gnu   libboost-locale1.83.0           libclang1-19            libreiserfscore0t64  linux-headers-6.14.0-1018-raspi  linux-tools-6.14.0-1018-raspi
    gir1.2-nautilus-4.0        libboost-program-options1.83.0  libfuse3-3              libsframe1           linux-image-6.14.0-1018-raspi    python3-packaging-whl
    libboost-context1.83.0     libboost-thread1.83.0           libgnutls-openssl27t64  libsigsegv2          linux-modules-6.14.0-1018-raspi  python3-wheel-whl
    libboost-filesystem1.83.0  libboost-url1.83.0              libllvm18               libstdc++-14-dev     linux-raspi-headers-6.14.0-1018
  Use 'apt autoremove' to remove them.

  Summary:
    Upgrading: 0, Installing: 0, Removing: 0, Not Upgrading: 0
    1 not fully installed or removed.
    Space needed: 0 B / 47.6 GB available

  Setting up initramfs-tools (0.150ubuntu3.1) ...
  update-initramfs: deferring update (trigger activated)
  Processing triggers for flash-kernel (3.109ubuntu6.2) ...
  Using DTB: bcm2711-rpi-4-b.dtb
  Installing /lib/firmware/6.17.0-1007-raspi/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/6.17.0-1007-raspi/./bcm2711-rpi-4-b.dtb
  Taking backup of bcm2711-rpi-4-b.dtb.
  Installing new bcm2711-rpi-4-b.dtb.
  flash-kernel: installing version 6.17.0-1007-raspi
  Copying kernel assets to /boot/firmware/new/
  cp: cannot stat '/boot/firmware/current/cmdline.txt': No such file or directory
  dpkg: error processing package flash-kernel (--configure):
   installed flash-kernel package post-installation script subprocess returned error exit status 1
  Processing triggers for initramfs-tools (0.150ubuntu3.1) ...
  update-initramfs: Generating /boot/initrd.img-6.17.0-1007-raspi
  Using DTB: bcm2711-rpi-4-b.dtb
  Installing /lib/firmware/6.17.0-1007-raspi/device-tree/broadcom/bcm2711-rpi-4-b.dtb into /boot/dtbs/6.17.0-1007-raspi/./bcm2711-rpi-4-b.dtb
  Taking backup of bcm2711-rpi-4-b.dtb.
  Installing new bcm2711-rpi-4-b.dtb.
  flash-kernel: installing version 6.17.0-1007-raspi
  Copying kernel assets to /boot/firmware/new/
  cp: cannot stat '/boot/firmware/current/cmdline.txt': No such file or directory
  run-parts: /etc/initramfs/post-update.d//flash-kernel exited with return code 1
  dpkg: error processing package initramfs-tools (--configure):
   installed initramfs-tools package post-installation script subprocess returned error exit status 1
  Errors were encountered while processing:
   flash-kernel
   initramfs-tools
  Error: Sub-process /usr/bin/dpkg returned an error code (1)

  
  If this matters, here is /boot/firmware/current and a find showing that no cmdline.txt file exists anywhere under /boot:

  root at pi4:~# find /boot -name cmdline.txt

  root at pi4:~# l /boot/firmware/current/
  total 98M
  drwxr-xr-x 3 root root 4.5K Feb  4 17:19 .
  drwxr-xr-x 4 root root  11K Jan  1  1970 ..
  -rwxr-xr-x 1 root root  32K Feb  4 17:18 bcm2710-rpi-2-b.dtb
  -rwxr-xr-x 1 root root  35K Feb  4 17:18 bcm2710-rpi-3-b-plus.dtb
  -rwxr-xr-x 1 root root  35K Feb  4 17:18 bcm2710-rpi-3-b.dtb
  -rwxr-xr-x 1 root root  32K Feb  4 17:18 bcm2710-rpi-cm3.dtb
  -rwxr-xr-x 1 root root  34K Feb  4 17:18 bcm2710-rpi-zero-2-w.dtb
  -rwxr-xr-x 1 root root  34K Feb  4 17:18 bcm2710-rpi-zero-2.dtb
  -rwxr-xr-x 1 root root  55K Feb  4 17:18 bcm2711-rpi-4-b.dtb
  -rwxr-xr-x 1 root root  55K Feb  4 17:18 bcm2711-rpi-400.dtb
  -rwxr-xr-x 1 root root  38K Feb  4 17:18 bcm2711-rpi-cm4-io.dtb
  -rwxr-xr-x 1 root root  56K Feb  4 17:18 bcm2711-rpi-cm4.dtb
  -rwxr-xr-x 1 root root  53K Feb  4 17:18 bcm2711-rpi-cm4s.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712-d-rpi-5-b.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712-rpi-5-b.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712-rpi-500.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712-rpi-cm5-cm4io.dtb
  -rwxr-xr-x 1 root root  78K Feb  4 17:18 bcm2712-rpi-cm5-cm5io.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712-rpi-cm5l-cm4io.dtb
  -rwxr-xr-x 1 root root  78K Feb  4 17:18 bcm2712-rpi-cm5l-cm5io.dtb
  -rwxr-xr-x 1 root root  77K Feb  4 17:18 bcm2712d0-rpi-5-b.dtb
  -rwxr-xr-x 1 root root  21K Feb  4 17:18 bcm2837-rpi-3-a-plus.dtb
  -rwxr-xr-x 1 root root  21K Feb  4 17:18 bcm2837-rpi-3-b-plus.dtb
  -rwxr-xr-x 1 root root  21K Feb  4 17:18 bcm2837-rpi-3-b.dtb
  -rwxr-xr-x 1 root root  20K Feb  4 17:18 bcm2837-rpi-cm3-io3.dtb
  -rwxr-xr-x 1 root root  21K Feb  4 17:18 bcm2837-rpi-zero-2-w.dtb
  -rwxr-xr-x 1 root root 4.2K Feb  4 17:18 blaize-blzp1600-cb2.dtb
  -rwxr-xr-x 1 root root  52K Feb  4 17:18 bootcode.bin
  -rwxr-xr-x 1 root root 2.7K Feb  4 17:18 en7581-evb.dtb
  -rwxr-xr-x 1 root root 7.2K Feb  4 17:18 fixup.dat
  -rwxr-xr-x 1 root root 5.4K Feb  4 17:18 fixup4.dat
  -rwxr-xr-x 1 root root 3.2K Feb  4 17:18 fixup4cd.dat
  -rwxr-xr-x 1 root root 8.3K Feb  4 17:18 fixup4db.dat
  -rwxr-xr-x 1 root root 8.3K Feb  4 17:18 fixup4x.dat
  -rwxr-xr-x 1 root root 3.2K Feb  4 17:18 fixup_cd.dat
  -rwxr-xr-x 1 root root  11K Feb  4 17:18 fixup_db.dat
  -rwxr-xr-x 1 root root  11K Feb  4 17:18 fixup_x.dat
  -rwxr-xr-x 1 root root 2.3K Feb  4 17:18 hat_map.dtb
  -rwxr-xr-x 1 root root  63M Feb  4 17:18 initrd.img
  -rwxr-xr-x 1 root root 1.5K Feb  4 17:18 overlay_map.dtb
  drwxr-xr-x 2 root root  31K Feb  4 17:19 overlays
  -rwxr-xr-x 1 root root 2.9M Feb  4 17:18 start.elf
  -rwxr-xr-x 1 root root 2.2M Feb  4 17:18 start4.elf
  -rwxr-xr-x 1 root root 790K Feb  4 17:18 start4cd.elf
  -rwxr-xr-x 1 root root 3.6M Feb  4 17:18 start4db.elf
  -rwxr-xr-x 1 root root 2.9M Feb  4 17:18 start4x.elf
  -rwxr-xr-x 1 root root 790K Feb  4 17:18 start_cd.elf
  -rwxr-xr-x 1 root root 4.7M Feb  4 17:18 start_db.elf
  -rwxr-xr-x 1 root root 3.6M Feb  4 17:18 start_x.elf
  -rwxr-xr-x 1 root root    5 Feb  4 17:19 state
  -rwxr-xr-x 1 root root  13M Feb  4 17:18 vmlinuz

  ProblemType: Bug
  DistroRelease: Ubuntu 25.10
  Package: flash-kernel 3.109ubuntu6.2
  ProcVersionSignature: Ubuntu 6.14.0-1019.19-raspi 6.14.11
  Uname: Linux 6.14.0-1019-raspi aarch64
  NonfreeKernelModules: zfs
  ApportVersion: 2.33.1-0ubuntu3
  Architecture: arm64
  CasperMD5CheckResult: unknown
  CloudBuildName: server
  CloudSerial:
   
  Date: Wed Feb  4 18:58:32 2026
  ProcEnviron:
   LANG=C.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=screen-256color
   XDG_RUNTIME_DIR=<set>
  RebootRequiredPkgs: Error: path contained symlinks.
  SourcePackage: flash-kernel
  UpgradeStatus: Upgraded to questing on 2026-02-04 (0 days ago)

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