Okay, so I need to fix a Samsung S908U-BIT6 that's dead and not booting. The user mentioned using EDL mode and USB debugging. Let me think through how to approach this.

First, I remember that EDL stands for Emergency Download Mode. It's used on Qualcomm devices to reflash the firmware when the device isn't booting normally. But I need to confirm if the S908U model uses a Qualcomm chipset. Let me check... Yes, many Samsung models, especially the Galaxy S series, use Qualcomm chips in certain regions, so EDL might be applicable here.

The device is dead, so the usual methods like recovery mode or Odin download mode might not work. The user wants to unbrick it using EDL. To enter EDL, sometimes you need to use a combination of buttons, but if the device is completely unresponsive, maybe a hardware method like shorting test points is required. I should look up if the S908U has specific test points to trigger EDL. Alternatively, using a USB cable in a specific way might help, but I'm not sure.

Wait, the user mentioned [DEBUG], which probably refers to USB debugging. But if the phone isn't booting, USB debugging might not be enabled. Unless it was enabled before the bricking. But if it's a hard brick, that's unlikely. So maybe EDL is the main route here.

Next, I need the right tools. For EDL, Qualcomm's Sahara and Firehose protocols are used. Tools like QFIL (Qualcomm Flash Image Loader) or specialized Samsung tools like Odin might be needed. But Odin usually requires download mode, not EDL. So perhaps using QFIL with the correct Firehose programmer file specific to the Samsung S908U. The challenge is getting that programmer file, as it's not always publicly available. Sometimes you can extract it from the firmware, but that requires some technical steps.

Alternatively, maybe the user can find a paid service or tool that provides the necessary files. I should mention that they might need to search for the exact Firehose ( .elf or .mbn ) file for their device model. Also, using a tool like EDL Client or other third-party software that supports Qualcomm EDL flashing.

Steps I think would be involved:

1. Enter EDL mode: Either via button combo (if possible) or test point shorting. For Samsung devices, sometimes holding Volume Up + Down and connecting USB does it, but if that doesn't work, opening the device and shorting the test points. I need to warn about the risks of opening the device.

2. Once in EDL, connect to a PC. The device should show up as Qualcomm HS-USB QDLoader 9008 or similar in Device Manager.

3. Use QFIL or another tool to load the Firehose programmer and flash the firmware. But where to get the firmware? They might need to download the stock firmware for S908U-BIT6 from a source like SamMobile or Frija, then extract the necessary files. However, standard firmware packages are for Odin, not EDL. So maybe converting or extracting the programmer from the firmware? That part is unclear to me. Perhaps they need to find a specific EDL package for their model.

4. Flashing the correct partitions: boot, recovery, system, etc. If the dead boot is due to corrupted partitions, reflashing them might revive the device.

5. Possible issues: Driver installation on the PC, finding the correct files, and authorization. Some EDL operations require authorized accounts or tokens, especially for Samsung devices, which might complicate things. If that's the case, they might need to go to a repair shop with authorized tools.

Also, the user mentioned DEBUG. Maybe they have access to ADB, but if the device is dead, ADB isn't accessible. Unless it's in a bootloop where ADB can be accessed briefly. But if it's completely dead, EDL is the only way.

Another thing to consider: battery level. Even if the device seems dead, the battery might be too low. Leaving it charging for a while before attempting EDL could help. Sometimes devices won't enter EDL if the battery is below a certain threshold.

Wait, Samsung's EDL mode might have specific requirements. I should check if there are any known methods for this particular model. Maybe looking up forums or XDA Developers for similar issues. For example, someone might have posted about how to enter EDL on the S908U and what tools they used.

In summary, the steps would be:

- Ensure the device has enough charge.

- Enter EDL mode via hardware method if necessary.

- Connect to PC, install drivers.

- Use QFIL with correct Firehose and firmware to flash.

- If successful, reboot the device.

But the challenges are getting into EDL without being able to use buttons, finding the correct Firehose file, and having the right firmware. Also, some Samsung models have anti-rollback protection or require signed firmware, which could be another hurdle.

I should also mention that if they're not experienced with EDL flashing, it might be risky and they could potentially make the device worse. Suggesting professional repair if they're unsure. Additionally, checking warranty status before attempting any hardware modifications.