[EVO 4G Q&A, Help & Troubleshooting] SLOSifl:
My EVO is currently stuck in the same state. I have spent a huge amount of time working on it, and have some information. I'm just dumping as much as I can remember in to this post, so excuse the lack of organization.

Before I go any further - I have not been able to fix the issue!

My phone was about as stock as possible when I took it to the Sprint store. They ordered me a new one and gave the broken one back. I have taken a few more risks now that my new one is on the way.

The initial problem started after flashing MIUI recently. The phone booted normally, but I noticed that the SD card was inaccessible. I would bet that the phone was refusing to charge over USB at this point as well, as that issue goes hand-in-hand with the sdcard problem.

The sdcard and its contents were fine. I later made a backup of the card and lost nothing.

Symptoms, high level info:

Phone immediately vibrates 5 times and begins flashing a green indicator, screen black at power on

Under unknown circumstances, the phone will display the white EVO boot screen before exhibiting the above behavior

Cannot exit this mode unless phone is unplugged and battery is removed

Bootloader can be accessed by holding volume down and power when starting fresh

SD Card is accessible in bootloader - indicates the problem is not purely hardware related

Fastboot can be used to temporarily (1 boot) gain access to sd card

Phone can be flashed with official PC36IMG

Phone can be set into RUU mode and flashed with official RUU

Official update.zip can be flashed from stock recovery

Qualcomm diagnostic tools can be used

Phone will remain in the installed OS for a very short amount of time

Bootloader shows S-ON, 'fastboot oem boot' shows Super CID and CID=111111111 instead of SPCS_001

Because one of my initial ideas was to flash a stock PC36IMG from the bootloader, I lost access to a custom recovery very early in the process. Other users may have better luck if they do not immediately flash a stock recovery.

Flashing PC36IMG is accomplished as usual. Vol- + Power.

To temporarily enable the sd card, disable Qualcomm Download mode:

Boot into bootloader

Wait for it to scan the SD Card

Select Fastboot (Power to select)

Plug into computer

Open a command prompt and ensure you have the fastboot executable

Command: fastboot oem enableqxdm 0

Exit fastboot

Select Clear Storage and select No to reboot OR

Select Recovery

The phone will boot into the OS. Under unknown circumstances, the phone will reboot. The amount of time can vary quite a bit. Enabling Airplane mode does not help. Using diagnostic tools to put the phone in Offline mode does not help.

If you would like to use Qualcomm diagnostic tools, the phone will have to be in diagnostic mode, rather than Download mode. The above steps will get you most of the way there, with the added annoyance that the phone will not enter proper diagnostic mode if left plugged in the entire time.

To ensure diagnostic mode correctly enables (or rather, that download mode disables):

Perform the fastboot command to disable qxdm

Unplug the phone

Navigate back to the bootloader, select Clear Storage

Select No (Vol-) to reboot

The white EVO boot screen will display

The screen will go black before the Sprint/4G animation plays

Plug the phone as soon as the white screen disappears, before the Sprint/4G animation

The phone will display in QPST Configuration without saying *Download* everywhere. The phone number will be incorrect, but that value is actually stored as a Directory ID in the NAM. In other words, it's okay.

The QPST Service Programming tool looked like a good place to start. If you would like to look at the configuration options for the EVO, you can start an offline connection using the profile "FFA/SURF QSD8650 Rev 2.0".

Note that the phone will always reboot after writing any values to the phone. This means you will have to pull the battery, unplug it, boot into fastboot, disable qxdm, boot into the OS each time.

You will need your MSL code for many of these applications. You can get it by calling Sprint and asking. They will not provide the code through email.

I can confirm that at least some changes in the Service Programming app will stick. I changed the banner, under the Display tab, to "Brick" (from Sprint), and it showed up in the Notification dropdown.

The NV util can read the values from the phone correctly.

QXDM can issue command to the phone.

ADB will not work. This limits the ability of tools like unrEVOked to do whatever they do. Getting ADB to work could be useful. Note that I did re-enable Debugging in the Setting->Applications menu to no avail. I believe this is a general side effect of this problem and perhaps a key symptom.

The bottom line is that I have run out of ideas. I have not found a setting in any of the QPST or QXDM tools that indicate this mode can be turned off. I have a hard time believing that there is some permanent switch in the Qualcomm SOC that says "always boot into this mode forever", but who knows.

Any suggestions would be great.

To summarize, I have installed a stock PC36IMG, update.zip, RUU. I have access to almost any setting in the phone, but cannot write to NV because it's in the S-ON state, which limits certain fastboot wipe options and the ability to push new images to system partitions from fastboot. I can, in theory, use the QPST Download software to move images if I can find one that might work.