I'm not familiar with Kaspersky but I'd think it can surely be disabled in the software. But, if you can't figure out how to do that, you could try killing it in Task Manager. Hit Ctrl/Alt/Del to open Task Manager, select it and then click on End Process. Another technique for disabling it would be to run msconfig (Start, Run, and enter msconfig in the Run box), select the Startup tab, find Kaspersky and uncheck the box next it. Click Apply, and OK. This will stop Kaspersky from launching during startup. Of course, you should reverse this, once you have updated your firmware.
And, yes, you could update firmware in Safe Mode.