[Droid Eris Q&A, Help & Troubleshooting] pkopalek:
If it's "Flashed" to cricket, you probably have much less work to do.

"Flash" is a buzz word that 'cool kids' that work at Cricket stores throw around, not really understanding what they're doing.

First of all, there's the PST settings. If you have a normal SenseUI ROM, you can access these settings with ##778 (call). Try that. Does that access PST settings? The password is 000000.

If so, all you'll have to edit here is MDN, MSID, and Home SID. You can get these numbers from Cricket customer service. Sometimes they call MSID something else. MDN is your phone number. Home SID depends on your physical area, among other things.

Once you have those, you can go through your PST settings and just confirm them with Ryan Mogul's PST settings thread, but DON'T use the PRL's he's saying to use (1039 or 38515 or whatever he uses, ignore the PRL file numbers, you're going to use 32100 or 32400 or something higher). If you need the PRL file, look at the attachment of this post. I put it there in a .zip file (unzip it first).

http://xdaforums.com/showthread.php?t=492824

After making the appropriate changes with your phone number, MSID, and SID, you can hit Menu > Commit modifications, and your phone will reboot.

If you've already had Cricket activate it from their side (aka scan or put in the Serial # of your phone into their system so that their network allows it to be used) then talk and text should work at this point. Does it?

If it does, you're ready for the 'flashing' part. Is the phone Rooted? If you're going to get the Android plan from Cricket, you don't technically need it to be, to have full functionality on Cricket. If you're on one of the lower plans (that has Mobile Web on it), and you want to use it still, you'll need to Root, and do this 'Flashing' thing everyone is talking about.

The Flash just tells all of the internet traffic to tunnel through wap.mycricket.com port 8080 (the web proxy that Cricket requires phones on the 'mobile web' plans to use -- the Android plan uses NO proxy, so that's why we don't need this step if you're going to go on that).

First, to root your phone (if it's not already rooted, and it's OK if it is), jcase's 1-click root works great.

http://xdaforums.com/showthread.php?t=742228

Download that and throw it on your phone. You can install it with ADB, or if you have wifi on the phone (whether or not it has cell service), you can just use the web browser on the phone and download it straight there. Or get tAttachApkInstaller from the Google Market (it's free), and send the eris one click root file (eris01root.apk or whatever it's called) to your Gmail account, then download it on your phone. tAttachApkInstaller will allow you to install it right from the Gmail App. There are other ways to approach getting the .apk on your phone, but either of those methods are pretty simple.

Then the flash itself. You want to download this flash, put it on your SD card (not in any particular folder, just ON the SD card), and flash it. Do NOT unzip things that you're supposed to flash. They're in .zip format on purpose. I promise. I'd download the Cricket v10 flash.

http://xdaforums.com/showthread.php?t=730289

If you're going to put a custom ROM on your phone; that's great. Do that first (through Amon-RA's recovery). I recommend xtrSense - http://xdaforums.com/showthread.php?t=726467 - it works with Cricket perfectly, is 100% stable and has all of the stock functionality and then some, AND you can still access ##778, which can come in handy when you have Cricket. But just about any ROM available (even 2.2 Froyo ROMs) will work just fine. Always flash the Cricket flash (the link above that I explained) AFTER you flash a ROM. You can do it right after, or you can do it a week later. But either way, you'll need to flash it to make it work.

If you flash a new ROM, you have to flash the Cricket v10 flash again. AND you have to get Autostart installed on the phone. That's free from Android Market.

After a reboot, your phone will eventually ask you for SuperUser permissions for Autostart. Allow it.

Profit.

Let me know where you get stuck in this process, I'll try to help. But it works, I promise you. If you can't figure out PST settings, take screenshots of each screen and gmail them to me. I'll figure it out for ya.

It seems like it's so complicated, and that one little mistake will make it not work. Not really. It will work with a couple of settings off. But it's just data entry. Follow all the directions, and nothing will fail. If something's not working, don't get overwhelmed, just go one step backward and make sure you've got it all right.

Good luck, soldier.