This is probably the top break down, but also the easiest going get going again.
It usually begins to show it's face by occasionally losing all power temporarily when the handlebars are turned to the extremes.
Not long after that, the solder underneath the key will fail and all power will be lost.
Here are the details.
https://pegfaq.dyndns.org:743/faq/doku.php?id=igwires
To repair, all you need is a pair of snips, a 5mm Allen key and some wire strippers. improvise if needs be!
taking off the headlight makes this so much easier but it can be done at a push from below the LHS of the headlight.
Find the wire heading to the ignition barrel and cut it about 10cm from the ignition barrel. Strip the outer protector and insulation from both of the wires coming from the wiring loom. Twist these wires together and hey presto you are back in business.
When the wires are twisted together the bike is on and cannot be turned off. Make sure your keys are in the ignition because if the transponder can't get a code from the keys it will think it is being hot wired (!) and it won't like it.
It is best to tape the wire that you have shorted somewhere where you can get at it so you can switch the bike off.
It remains safe when you removed the keys because the immobiliser will operate if someone rewires it up without the key being present.
The permanent fix is to resolder the wires in the wiring loom using a really good hot solder and stop the wire from flexing about too much. it's worth installing a wiring block so if something similar happens again, it can be unscrewed and wired together without cutting.