Hack-A-N900/Usb Recovery Mode

I bricked my maemo setup several times. Often the underlying problem would have been trivial to fix, if i had a way to access the rootfs. Patching bootmenu enables us to boot a minimal system with just usb network and sshd enabled. that's still not optimal because this solution relies on rootfs being accessible. why? - 1 2 - in short, during boot process no seperate initrd is utilized - in fact the rootfs is misused for it -.- . the bootmenu script circumvents that by redirecting the pivot_root call issued by /sbin/preinit, which is a pretty dirty - yet effective hack. hmmm... just an idea, but why not use the rootfs for initrd purposes only?... sshd will be using settings from the rootfs.

Prerequisites

• First Steps
• Development - Software sources for apt, installing "patch".

Install bootmenu

Login via ssh to your n900 and:

# Get the bootmenu package:
wget http://www.daimi.au.dk/~cvm/bootmenu_1.6_armel.deb

# Install bootmenu package
dpkg -i bootmenu_1.6_armel.deb

# Install bootmenu script
install_bootmenu

Patch bootmenu.sh to fix key bindings and enable usb recovery mode

cd /
wget http://metalab.at/wiki/images/4/40/Bootmenu_n900usbrecov.patch
patch -p0 < Bootmenu_n900usbrecov.patch

If you like you can edit /bootmenu.conf and adjust the ip address the usb interface will start with in recovery mode:

# IP address for USB networking
USB_IP=192.168.2.15

Enable R&D mode and disable watchdogs

Enable flasher mode and execute following on your pc:

./flasher-3.5 --set-rd-flags=no-omap-wd
./flasher-3.5 --set-rd-flags=no-ext-wd
./flasher-3.5 --enable-rd-mode

Boot into recovery mode

Reboot the device with the keyboard slide out(!). When the boot menu appears you can either select a boot entry or press "CTRL" to boot usb recovery mode.