I think you will find your answer in the firmware upgrade section of the Stacking Guide for the M8024-k, on page 43. unit image1 image2 current-active next-active ----- ------------ ------------ ----------------- ----------------- 1 4.2.0.1 4.2.0.2 image1 image1 2 4.2.0.1 4.2.0.2 image1 image1 3 4.2.0.2 4.2.0.1 image2 image2 4 4.2.0.1 4.2.0.2 image1 image1 The current-active column now shows the same values as the next-active column. The next step is to activate the image that contains the new firmware. In this example, Units 1, 2, and 4 will need image2 activated, and Unit 3 will need image1 activated. Perform the following commands. console#boot system 1 image2 Activating image image2 .. console#boot system 2 image2 Activating image image2 .. console#boot system 3 image1 Activating image image1 .. console#boot system 4 image2 Activating image image2 .. Here is the link to the paper: [URL] Hope this helps. -Victor
I attempted to update the firmware on a PC8024-k 2 switch stack to 5.1.5.1.  After the update this is what I get: unit image1      image2      current-active next-active---- ----------- ----------- -------------- --------------1    5.1.2.3     5.1.5.1     image2         image22    5.1.5.1     5.1.2.3     image2         image2 According to this table, unit 2 will boot the old image next time it reboots; how can I change it? 
update firmware on PC8024-k blade chassis stack?