I'm not sure where to report this, so please reassing to the
appropriate package.

In Trixie my HP ScanJet was working properly, I could scan using
simple-scan.

Some weeks ago I upgraded to Testing/Forky. Now I wanted to scan. The
scanner is detected, (e.g. in simple-scan), but when I want to
connect, scanning fails because a connection to the scanner could not
be established.

Also in the display of the scanner the computer is not found.

The cabeling for the scanner is unchanged.

helge@twentytwo:~$ scanimage -L
device `v4l:/dev/video0' is a Noname Hauppauge WinTV-HVR5525 virtual device
device `hpaio:/usb/HP_ScanJet_Pro_4500_fn1?serial=CN0C3D904B' is a Hewlett-Packard HP_ScanJet_Pro_4500_fn1 all-in-one

helge@twentytwo:~$ LC_ALL=C scanimage > pic.pnm
Output format is not set, using pnm as a default.
scanimage: sane_start: Invalid argument
helge@twentytwo:~$ file pic.pnm
pic.pnm: empty

root@twentytwo:~# lsusb
…
Bus 003 Device 009: ID 03f0:5405 HP, Inc HP ScanJet Pro 4500 fn1
…

root@twentytwo:~# sane-find-scanner

  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

found possible USB scanner (vendor=0x03f0 [HP], product=0x5405 [HP ScanJet Pro 4500 fn1]) at libusb:003:009
  # Your USB scanner was (probably) detected. It may or may not be supported by
  # SANE. Try scanimage -L and read the backend's manpage.

  # Not checking for parallel port scanners.

  # Most Scanners connected to the parallel port or other proprietary ports
  # can't be detected by this program.

Hi, Helge,

This may have the same origin as #1137654 [hplip cannot download plugin].
According to

https://developers.hp.com/hp-linux-imaging-and-printing/binaryplugintable

that model seems to require a binary plugin for scanning. Did you find
any message about plugins?

Thorsten, please consider using an updated hp+hplip gpg key in
debian/upstream/signing-key.asc for hplip package. It will be installed with
the package and should fix #1137654, and will also help to know if this is
the same problem or not.

Thanks for your contribution to Debian,

Hello Agustin,
sorry for the belated reply, I just returned from Summer vacation
(without computer :-)).

Am Mon, Jul 20, 2026 at 06:44:18PM +0200 schrieb Agustin Martin:
simple-scan: common/utils.c 140: validate_plugin_version() Plugin version[3.22.10] mismatch with HPLIP version[3.26.4]

This refers to the same plugin version as in #1137654.

This would be really great.

Besides getting my scanner working, is there anything else I
could/should try in the meantime?

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1137654#10
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1137654#15
provide some workaround steps. Should I try (some of) them as well?

Greetings

          Helge

Hello Augustin,
it seems like there is no action on this bug report, unfortunately.

Am Mon, Jul 20, 2026 at 06:44:18PM +0200 schrieb Agustin Martin:

So I followed the instructions in #1137654. For the record, the public
key for verification can be found here:
https://developers.hp.com/hp-linux-imaging-and-printing/hplipDigitalCertificate.html

To install the plugin, I did *not* call hp-plugin. As already
discovered in #1137654 this fails.

Instead I obtained "hplip-3.26.4-plugin.run". As I was able to verify
the authenticity with the key obtained above, I executed it (as
non-root!) and it installed the plugin without problem.

And now scanning works again!

I CC'ed 1137654, as this might make printer installation possible as
well.

That would be perfect! Using #1137654 with my instructions above
hopefully make this possible.

Greetings

         Helge

We believe that the bug you reported is fixed in the latest version of
hplip, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1142304@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Thorsten Alteholz <debian@alteholz.de> (supplier of updated hplip package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sun, 23 Aug 2026 18:14:59 +0200
Source: hplip
Architecture: source
Version: 3.26.4+dfsg0-4
Distribution: unstable
Urgency: medium
Maintainer: Debian Printing Team <debian-printing@lists.debian.org>
Changed-By: Thorsten Alteholz <debian@alteholz.de>
Closes: 1137654 1142304
Changes:
 hplip (3.26.4+dfsg0-4) unstable; urgency=medium
 .
   * debian/upstream/signing-key.asc
     replace old key by new one, downloaded from
https://developers.hp.com/hp-linux-imaging-and-printing/ \
         hplipDigitalCertificate.html
     (Closes: #1137654)
     (Closes: #1142304)
Checksums-Sha1:
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 23bfcb1ee0322e4d69627b2335c9e9443c440e30 150876 hplip_3.26.4+dfsg0-4.debian.tar.xz
 37bec38ce52acf3001478b3c944134a566dec079 20165 hplip_3.26.4+dfsg0-4_amd64.buildinfo
Checksums-Sha256:
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 f2dcbca9e7e7586e8d0508b2d37752a80aca5ab996d064fc8852390e8e9f2817 150876 hplip_3.26.4+dfsg0-4.debian.tar.xz
 c82b6d395b144773c1a9e56195cfc725dcadef2976c91f70cbe3b5951700e437 20165 hplip_3.26.4+dfsg0-4_amd64.buildinfo
Files:
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 2aec63441638913cd48e9739428f7352 150876 utils optional hplip_3.26.4+dfsg0-4.debian.tar.xz
 ebb1bab4927f3a070b1851c7dd4e78af 20165 utils optional hplip_3.26.4+dfsg0-4_amd64.buildinfo
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