Boot ROM Guide
Most firmware updates are automatically installed when you update or upgrade OS X. While signing up, please copy the boot ROM version in your machine and paste it here:
1. Open System Information
First, click on the Apple Menu in the top left corner of your screen
Then, select "About this Mac"
On the "Overview" tab, select "System Report"
2. Select the Hardware section to view the Model Identifier, Boot ROM version, and SMC version numbers.