Hi Fishraiders,
I purchased a HDS5 combo about 10 months ago and since I purchased it there has been 2 software upgrades which I've done by downloading the update to an SD card and then updating the sounder. It has worked perfectly every time and the great thing about it is that every time you upgrade the software the unit ends up with a hand full of extra features.
I don't know about the HDS5X but with the combo it is very easy. Just go into the Australian Lowrance site www.lowrance.com.au/ then click on 'DOWNLOADS', 'PRODUCT SOFTWARE UPDATES' then just scroll about half way down till you get to 'HDS - ALL units - 4.0 software version and demonstration files' click on this and it will give you step by step instruction for PC or MAC system. Very easy to carry out.
I got myself an extra power lead well worth it. You can then play around with it at home whilst sitting around having a beer instead of wasting time on the boat. I got my lead of the shelf at $^%*&&($% but I can't remember how much I paid for it. Have fun it's a great little sounder. All I need now is the structure scan upgrade, maybe next year, mmmm only a week away.........