Not so bad, but if your server room is actually a storage closet with the rack eight feet in the air so you have to stand crooked on a ladder, it's a pain in the back (and a lower, rear facing location as well).
The upgrade process is in fact, quite painless.
- Just fire up your ASDM
- Go to Tools > Upload Software from Local Computer...
- Choose your Image to Upload: (ADSM first, then ASA later)
- Browse Local Files... to add the image (.bin file)
- Click Upload Image and follow the prompts to finish (they vary depending on image uploaded)
Following the process above for our brand new firewall, the ASDM image reloaded properly to the latest version while the device was running, the ASA software however, did not. Rebooting the ASA loaded everything properly and I was on my way. (Or was I? That's blog entry to come...)