Wow - Blast from the Past.
I had some private conversations with Scott, but I never posted fearing the wrath of Dish.
As far as I know talk of hard drive upgrading is ok. I also feel strongly that a user should be allowed to replace a failed HDD himself.
Most initial info comes from the dishmod group over at Yahoo. There's a few people really playing with this. Especially interesing is hard drive swapping on the 50x series (which sometimes requires a reflash).
Anyway, I don't have a 921 anymore, but did some hdd swapping. Ghosting the drive does work, but swapping actively for space has many problems....
1) If you swap in a bigger drive, it'll work, but the partition space is fixed so you don't get any more space.
2) Timer events are stored on the HDD
3) Software upgrades are a problem. Remember the 921 is not storing the os in flash - it's on the HDD). When the software download occurred the drive in the unit upgraded fine, but when I swapped in the other drive it actually when backwards to an even earlier software rev (now two behind), and the 921 made no atttempt to download....
How you may ask (some educated guesses here)?
There are two OS partitions on the 921 HDD (probably for safety). My believe is that the EEPROM/Flash uses a pointer to decide which partition to boot from.
When a new OS downloads it goes to the inactive partition. Then, after the software is validated the pointer is changed to the other partition. The current software rev must also be stored in the EEPROM.
So when I installed the other drive, the OS pointer was now grabbing the other partition with prior software version (since that dive hadn't seen the latest download). Since the software rev in the EEPROM was current the box didn't attempt to redownload from the stream.
I believe I then had to reghost copy the partitions (don't remember if I lost stored programming).
Bottom line, I only swapped the drives a couple of times. Once before a 1 week vacation and I didn't want to delete programming.
Oh well, I now have a 622 and hopefully dish will eventually get external HDD support working (I rather not mess with the box - sure wasn't too thrilled having to resolder the connections of my HDMI port).
The new series boxes (522, 625, 942, 622) are a lot different since they are booting from flash. I haven't tried it myself, but I believe they will automatically initialize a new HDD.
I believe the software still has a list of "supported" hard drives so only specific models will work (unlike the 921 which has no such list).