[G2 and Desire Z General] kusuriurikun:
As you noted, there is no gps.vision.so in Froyo--one thing you MAY try is a gps.vision.so from the latest OTA update for G2, which is reported (WITH STOCK) to work with that radio. (And yes, I looked--I actually do have a ripped version of the last Froyo ROM for G2; the GPS and general "talking to radios between kernel and chip" infrastructure changed substantially between Froyo and Gingerbread, with Froyo largely doing it through the radio RILs whilst Gingerbread uses a dedicated driver of the form gps.(YOUR MODEL HERE).so.)

That said--I do know a number of folks who DO successfully use the "old Froyo radio" with very recent Gingerbread ROMs and who have successfully used it--with working GPS--in stock T-Mo US Gingerbread ROMs that are only rooted and de-odexed.

The best thing I could suggest is to back up the gps.vision.so you use now, use the installer for 10.04.xx radios and see if it behaves. (If not, you can always revert back.)

The one thing I'm now wondering about (especially with multiple reports of incompatibility with the gps.vision.so from the latest T-Mo US OTA and the 08.04.30 radio) is if newer radios may have more compatibility with the kernels used in AOSP ROMs. If a combo with the OTA gps.vision.so and the old Froyo radio (26.03.02.26_M) works, we know there's some sort of flakiness going on with the actual 08.04.30 radio itself; if (say) the gps.vision.so from a Sense ROM works but not the OTA update gps.vision.so, we know there's some sort of incompatibility between that driver and 2.3.5-based AOSP ROMs.

(Among other things, something that's definitely throwing my curiosity up on this is knowing that the 10.04.xx radios are from Sense ROMS which are much higher versioned (internally by HTC) than the T-Mo US OTA update; I'm thinking that they may be working from an "almost stock" base and then doing updates, code patching, etc. as they "Sense up" the non-US ROMs. In other words, the US ROM may be actually based on an older code-base (as far as HTC-tweaked drivers, etc.) go than the Sense ROMs and may be the "base core" for what gets "Sensed up". Especially throwing my curiosity up is the drastic variation between T-Mo US OTA version internally (something like 2.15.131.3 is the internal version number of the OTA update with radio 08.04.30) and Sense ROMs with known working radio/gps.vision.so pairs (which are in the 2.42.xx internal version range, including the (previous to T-Mo OTA) 2.42.405.2 HTC-WWE ROM with 10.04.03 and the Bell Mobility OTA ROM with radio 10.04.03).)

(The fact that multiple people in the RIL-matching thread have noted issues with the 08.04.30 radio (and particularly that radio) and RIL matching actually occasionally causing data issues, etc. points to either a kernel change (between the "base stock" ROM that T-Mo US users get and the "Sensed up" stuff that the Rest Of The World gets) or possibly some sort of bug in the radio that mostly shows up in AOSP ROMs and Sense ROMs when RIL matching is attempted--and this may also be preventing gps.vision.so matching (which is related in that we're matching radio drivers) from working successfully.)

(Put more bluntly--I rather suspect something may have changed JUST enough with the tweaks that HTC has done with Sense-based stock ROMs (and drivers for them) over the relatively "Stock" T-Mo "Senseless" ROMs that either there's incompatibility in the driver or incompatibility in the radio. I'm personally suspecting "driver", because I've had GPS break on a stock T-Mo US Gingerbread ROM when I put the Bell 10.04.12 radio on, but it could be a little from column A and a little from column B.)

(This is only a hunch, though, and it honestly requires more experimentation with more radios and known working gps.vision.so versions. I'd be ecstatic if I were to get a report that the gps.vision.so from a 10.04.03-using ROM worked with 08.04.30, or if one of the older radios worked well that's been proven to play well with T-Mo US.)