July 3, 2010 Update on WiMAX Issues

This update is in regards to the first version of the EVO 4G OTA2 patch that we released on Tuesday morning. Users that applied this patch (or other similar WiMAX patches created by other users) lost WiMAX (4G) connectivity on their devices. The symptom of this issue is that when the 4G radio is turned on, shortly after it attempts to connect to a 4G network, the radio turns itself off. If you are having any other symptoms (such as the radio continually 'scanning', or the radio refusing to connect to a network, but remaining turned on), then this update does not apply to your device.

Shortly after we published the update, we began receiving reports that users who applied it were unable to connect to the WiMAX network. We removed it from our site, but others continued to distribute copies of the zip and other updates that used the same mechanism. We believe that a small number of users may have applied the update.zip that we released. Over the past days, our team has been performing research on what happened to these devices, and what steps we can take to restore functionality. Our findings are summarized below.

When the WiMAX radio image is flashed using flash_image (or something equivalent to it), then certain important pieces of WiMAX data get overwritten due to a design flaw in Sprint's firmware where these data are inadequately protected from modification. The official over-the-air update (OTA) does not destroy these data because it uses undocumented functionality that transfers them to the new firmware before reflashing. Some of these data can be recreated, but at this time, we do not have the capability to recreate all of these data. When these data are not present on the phone, the radio appears to crash when it connects to the WiMAX network.

Currently, we do not believe that there is a “safe” mechanism to upgrade the WiMAX firmware without taking the official OTA. We advise against applying any “WiMAX-only” update.zip files to your phone.

The only fix right we have tested ourselves at this time is to restore a backup of the WiMAX partition taken from the same device before applying the update. We strongly urge users not to further experiment with the WiMAX partition on their devices; doing so may result in damage to your phone or your phone being permanently banned from Sprint's network. Over the coming week, we hope to be able to work with Sprint to come to a resolution; without this, however, no safe solution is in sight.

We apologize profusely for the trouble this has caused you. We do our best to quality-check every file that we publish before we publish it; in this case, none of our testers reside in 4G service areas, and so none of our testers could verify the WiMAX upgrade's functionality. Obviously, this was insufficient. In the future, we will not include radio updates of any kind without fully testing on a variety of devices.

The unrevoked Team

public/jul3update.txt · Last modified: 2010/07/03 14:35 by joshuawise
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