I presume you're using Windows due to the PuTTY reference? (Yes, I am aware it exists for Linux but it sucks IMHO for Linux - much prefer 'ssh' and gvfs' SFTP functionality under Linux, but anyway...)

I assume you're using Windows (XP), so:

1) Flash this kernel (http://tablets-dev.nokia.com/maemo-d...ndows_v0.4.zip) (it's an officially released image from Nokia, don't worry) as it has a fix for USB Networking under Windows
* I did this with Ubuntu running under VMWare Workstation running on XP. Worked a treat.

2) Start up USB Networking from the bootmenu. When/If asked to install drivers, point Windows' "Add New Hardware Wizard" to inf in zip.

3) Open "Network Connections" and find the "Local Area Connection" for your tablet. Configure like this:
* Make the IP address one digit less than what is reported on the tablet (so if tablet says "192.168.2.15", put IP of "192.168.2.14") in that field.
* Subnet mask: 255.255.255.0
* Default gateway: IP that is on tablet's screen.
Leave DNS server addresses blank.
N.B: As you may have guessed, I'm not up on networking so...

4) Telnet into tablet (telnet (tablet IP))
5) mkdir /tmp/root/
6) mount -t jffs2 /dev/mtdblock4 /tmp/root/
7) cd /tmp/root/, edit file, profit!

Be quick, BTW. Tablet will reboot after ~10 mins unless you enable RD-Mode or run /usr/sbin/dsmetool --root-mounted