[Sprint Samsung Galaxy S III] rexograff:
Sorry to blow up your thread. I responded like that, with so much behind it, because I'm in the same boat, and you sounded like you were asking the same questions I am. I imagine there are quite a few of us who took advantage of that great deal, and are trying to figure this out as well.

Me neither!

Drop in on that link, other gus' tutorial, and read the Overview. I'm going by that, because it crystallized quite a few bare hints and known issues I'd found elsewhere, earlier in the search, into a coherent explanation that fits the device's behavior. As he explains, "The Sprint MD4 firmware uses a Jellybean bootloader, while Virgin Mobile’s firmware uses a bootloader for ICS. If you were eager to install CM10.1 and attempted to do so, the “assert failed” errors you saw were because all versions of CM after 10.1 require a Jellybean bootloader - and, like I said, our phones have an ICS bootloader. Thus, we need Sprint’s Jellybean bootloader to install CM10.1."

While some of the info may have become dated since July, and it's a little light on sources, the premise fits most of the Please Help! complaints in Sprint/VM ROM forums. The common thread I see running through most every VM forum is the inability of anyone with our brand and model to upgrade past a certain point. And system upgrades from VM seem to be deliberately keeping us behind the times, until they're good and ready to allow us their version of newer Android, whatever that may be. But, isn't that why we root and flash in the first place?

I'm not entirely sure, I'm no Developer. An advanced beginner on other phones, maybe, but a Samsung rookie, for sure. I've had this phone about a week, and I've wandered into forums blindly, picking up hints along the way, much the same way I did with the OG. Only then, there was a wealth of learning available, and it was pretty easy to sift through the good, bad, and expired, until I had a working body of knowledge that let me use the device safely.

In this case, most of what's to be had stems from d2spr. Truly good and current information on the VM L710 is rare, and scattered. (What I wouldn't give for a current comprehensive list of VM bootloaders, or VM Stock ROM changelogs, or... Something.)

I think you got it right, the line seems to be drawn at 4.2.1, or earlier builds of CM 10.1. While it looks like Google built in some overlap, Android past that point requires calls that only a JB bootloader can answer. The consistent explanation by devs or long time modders who visit these few forums, is that the information provided when the flash fails all point to 'ro.bootloader', and lists a set of four bootloader/modem/firmwares that it's looking for, for example L710VPBMD4, all VPB. (MD4 may be dated by now, but it was the new one back in July, and its still "newer" android-wise than L710VPAMD7. The crazy part of their method is to go into the d2spr MD4 update package and replace Sprint's modem with punkmaxx's extracted VM modem. DIY awesome.)

That illustrates part of the deeper problem right there. The VM SGS3 has only been around a few months, and it usually takes some time for experienced devs to gravitate to a device. But, that's considering new devices. The S3 is over a year old, it's replacement is already out, and while other models like the AT&T, Verizon, and T-Mobile versions, and the I9300, have gotten decent attention and support from the experienced mod community over the last year, Sprint's version has gotten a bit less. And our VM has barely registered, (here's Cyanogenmod's semi-official position on the VM L710), let alone been given it's own d2vmu page on any site. (Your original post was the first mention I found of that online.)

And, like the few folks providing us options, like other gus, and punkmaxx, and you, I hope I can help change that.

This is a good device, if we can get past Virgin Mobile, and make it our own.

---------- Post added at 05:41 PM ---------- Previous post was at 05:26 PM ----------

Crazy thing happened... In trying to replicate the failed install, to provide you with the ro. bootloader info, the install succeeded. It seems the modified bootloader worked, but only after a full reboot back into system, which was still my VM Stock (rooted). Once back into recovery (TWRP), it worked. Of course, I was trying CM 10.2, and it got caught in a bootloop, and I had to do a full restore into Stock, but it made it that far.

I remember your description of pretty much the same thing. Is that what happened, even without the bootloader install?

(I may try again with 10.1. I just miss Privacy Guard.)