Can anyone confirm if the current baseband_v9.zip file actually works? I suspect maybe the file has been corrupted on the box.com servers, or that the file is for a completely different device.
Do yourself a favor if you're testing this, and not only do a nandroid backup beforehand, but also download baseband_lucid_v8.zip in case baseband_v9.zip does for you what it did for me (and maybe even use dd to backup your original mmcblk0p14 [baseband.img] and mmcblk0p1 [firmware.img] so you can restore your original firmware later).
For me, the baseband_v9.zip file caused a soft brick boot loop (actually, it caused a partial hard brick, because it wouldn't even enter Emergency/Download mode after flashing v9, that's when I started to freak out). It would have been a legitimate hard brick if CWM didn't have the ability to establish a USB mass storage connection and allow me to upload baseband_lucid_v8.zip to it, which recovered the device.
After recovering the device, Android seemed corrupted and I had to restore the nandroid backup. Then I downloaded baseband_v9.zip a second time using a separate connection and second device in case file corruption happened on my end, and both copies of baseband_v9.zip did the same exact thing to the device.
Can anyone help? Does anybody even care anymore?
P.S. What's incredibly odd is that before flashing baseband_v9.zip, I examined the contents of baseband_v9.zip, I could see that flashing it replaces firmware.img and baseband.img, so I used adb shell and the dd command to make backup copies of my original firmware.img and baseband.img. When v9 bricked my phone, I created a custom flashable zip that restored my original firmware.img and baseband.img, then I flashed back to my original baseband, but it didn't change or fix anything. Why would completely undoing the v9 baseband flash still not fix it? I've been flashing for years and this part I do not understand.
P.P.S. I think I found an error in the changelog, or something, but maybe it's the source of this whole disaster. It says the RIL files for build B4 were updated to be used with baseband_v9 on 9/30/13. However the B4 filename indicates it was compiled on 8/23/13. That doesn't make sense.
P.P.P.S. I can't get an LTE connection with baseband_v8, and I think it may be because I need baseband_v9. Either way, the changelog in post #3 recommends everybody use baseband_v9 with the latest release, and I simply can't get it to work (which build date is the latest release?), but it may be due to the B4 versioning issue that I just mentioned.
Thanks for any help...