firmware pb with HP PSC 2355

My printer is an HP PSC 2355 "all in one".
I am running gentoo linux on amd64.

My printer worked fine for several months (printer AND scanner were OK) but recently it stopped working complaining about the color cartridge:
"Remove and check color cartridge".
This message is displayed on the printer at the very beginning and prevent from doing anything. (even using the printer as a simple photocopier)

According to HP web site, it seems to be a known problem of the device and I need to update my printer firmware.
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00249451&lc=en&cc=us&dlc=en&os=228&product=422000&rule=44430&lang=en#

Is my understanding ok?
If I am right, can you tell me where to get this firmware. I only found windows ".exe" on HP web site and linux driver on openprinting.org.

Moreover may be you could give me the right procedure to update my printer firmware. I have this "hp-firmware" tool but the help is not very precise and I did not manage to found some documentation.

Thanks by advance for any help.

bazaar ~ $ cat hp-check.log

hp-check[29499]: info: :
Initializing. Please wait...
l'ordonnanceur tourne

1.2.12

Linux Bazaar 2.6.20-gentoo-r8 #6 SMP PREEMPT Tue Jun 19 23:43:06 CEST 2007 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ AuthenticAMD GNU/Linux

hp-check[29499]: info: :
hp-check[29499]: info: :---------------
hp-check[29499]: info: :| SYSTEM INFO |
hp-check[29499]: info: :---------------
hp-check[29499]: info: :
hp-check[29499]: info: :Basic system information:
hp-check[29499]: info: :Linux Bazaar 2.6.20-gentoo-r8 #6 SMP PREEMPT Tue Jun 19 23:43:06 CEST 2007 x86_64 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ AuthenticAMD GNU/Linux
hp-check[29499]: info: :
hp-check[29499]: info: :Distribution:
hp-check[29499]: info: :gentoo 0.0
hp-check[29499]: info: :
HPOJ running?
hp-check[29499]: info: :No, HPOJ is not running (OK).
hp-check[29499]: info: :
hp-check[29499]: info: :Checking Python version...
hp-check[29499]: info: :OK, version 2.4.4 installed
hp-check[29499]: info: :
hp-check[29499]: info: :Checking PyQt version...
error: NOT FOUND OR FAILED TO LOAD!
hp-check[29499]: info: :
hp-check[29499]: info: :Checking SIP version...
error: SIP not installed or version not found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for CUPS...
hp-check[29499]: info: :Status: l'ordonnanceur tourne
hp-check[29499]: info: :Version: 1.2.12
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for Reportlab...
warning: Not installed.
hp-check[29499]: info: :
hp-check[29499]: info: :----------------
hp-check[29499]: info: :| DEPENDENCIES |
hp-check[29499]: info: :----------------
hp-check[29499]: info: :
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: cups - Common Unix Printing System...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: cups-devel- Common Unix Printing System development files...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: gcc - GNU Project C and C++ Compiler...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: GhostScript - PostScript and PDF language interpreter and previewer...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libcrypto - OpenSSL cryptographic library...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libjpeg - JPEG library...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libnetsnmp-devel - SNMP networking library development files...
error: NOT FOUND! This is a REQUIRED dependency. Please make sure that this dependency is installed before installing or running HPLIP.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libpthread - POSIX threads library...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libtool - Library building support services...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: libusb - USB library...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: make - GNU make utility to maintain groups of programs...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: PIL - Python Imaging Library (required for commandline scanning with hp-scan)...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: ppdev - Parallel port support kernel module....
error: NOT FOUND! This is a REQUIRED dependency. Please make sure that this dependency is installed before installing or running HPLIP.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: PyQt - Qt interface for Python...
error: NOT FOUND! This is a REQUIRED dependency. Please make sure that this dependency is installed before installing or running HPLIP.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: python-devel - Python development files...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: Python 2.3 or greater - Required for fax functionality...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: Python 2.2 or greater - Python programming language...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: Reportlab - PDF library for Python...
warning: NOT FOUND! This is an OPTIONAL dependency. Some HPLIP functionality may not function properly.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: SANE - Scanning library...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: SANE - Scanning library development files...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: scanimage - Shell scanning program...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for dependency: xsane - Graphical scanner frontend for SANE...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :| HPLIP INSTALLATION |
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :
hp-check[29499]: info: :
hp-check[29499]: info: :Currently installed HPLIP version...
hp-check[29499]: info: :HPLIP 2.7.10 currently installed in '/usr/share/hplip'.
hp-check[29499]: info: :
hp-check[29499]: info: :Current contents of '/etc/hp/hplip.conf' file:
hp-check[29499]: info: :# hplip.conf. Generated from hplip.conf.in by configure.

[hpssd]
# Note: hpssd does not support dynamic ports
# Port 2207 is the IANA assigned port for hpssd
port=2207

[hplip]
version=2.7.10

[dirs]
home=/usr/share/hplip
run=/var/run
ppd=/usr/share/ppd/HP
ppdbase=/usr/share/ppd
doc=/usr/share/doc/hplip-2.7.10
icon=/usr/share/applications
cupsbackend=/usr/libexec/cups/backend
foomatic=/usr/share/foomatic

# Following values are determined at configure time and cannot be changed.
[configure]
network-build=no
pp-build=no
gui-build=no
scanner-build=yes
fax-build=no
cups11-build=no
doc-build=no
shadow-build=no
foomatic-xml-install=no
foomatic-ppd-install=no
internal-tag=2.7.10.11

hp-check[29499]: info: :
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :| INSTALLED PRINTERS |
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :
hp-check[29499]: info: :
warning: No queues found.
hp-check[29499]: info: :
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :| SANE CONFIGURATION |
hp-check[29499]: info: :----------------------
hp-check[29499]: info: :
hp-check[29499]: info: :'hpaio' in '/etc/sane.d/dll.conf'...
hp-check[29499]: info: :OK, found. SANE backend 'hpaio' is properly set up.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking output of 'scanimage -L'...
hp-check[29499]: info: :device `hpaio:/usb/PSC_2350_series?serial=HU54EFRB96KJ' is a Hewlett-Packard PSC_2350_series all-in-one

hp-check[29499]: info: :
hp-check[29499]: info: :---------------------
hp-check[29499]: info: :| PYTHON EXTENSIONS |
hp-check[29499]: info: :---------------------
hp-check[29499]: info: :
hp-check[29499]: info: :Checking 'cupsext' CUPS extension...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking 'pcardext' Photocard extension...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking 'hpmudext' I/O extension...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :Checking 'scanext' SANE scanning extension...
hp-check[29499]: info: :OK, found.
hp-check[29499]: info: :
hp-check[29499]: info: :
hp-check[29499]: info: :-----------------
hp-check[29499]: info: :| USB I/O SETUP |
hp-check[29499]: info: :-----------------
hp-check[29499]: info: :
hp-check[29499]: info: :
hp-check[29499]: info: :Checking for permissions of USB attached printers...
hp-check[29499]: info: :HP Device 0x4911 at 002:004:
hp-check[29499]: info: : Device URI: hp:/usb/PSC_2350_series?serial=HU54EFRB96KJ
hp-check[29499]: info: : Device node: /dev/bus/usb/002/004
hp-check[29499]: info: : Mode: 0664
hp-check[29499]: info: :getfacl: Removing leading '/' from absolute path names
# file: dev/bus/usb/002/004
# owner: root
# group: lp
user::rw-
group::rw-
other::r--

hp-check[29499]: info: :
hp-check[29499]: info: :-----------
hp-check[29499]: info: :| SUMMARY |
hp-check[29499]: info: :-----------
hp-check[29499]: info: :
error: 7 errors and/or warnings.
hp-check[29499]: info: :
hp-check[29499]: info: :Please refer to the installation instructions at:
hp-check[29499]: info: :http://hplip.sourceforge.net/install/index.html