Official Huawei GR5 2017 / Honor 6X (Berlin BLN) Firmware to Fix Bootloops, Lag & Update Failures

The Huawei GR5 2017 and Honor 6X (codenamed “Berlin”, models BLN‑L21, BLN‑L22, BLN‑L23, BLN‑AL10/20/30/40, BLN‑TL00/10, plus related GR5 KII‑L21) share a solid mid‑range hardware platform built around the HiSilicon Kirin 655 chipset, 5.5‑inch Full HD display, 3–4 GB RAM, 32–64 GB storage, dual‑camera system, and a 3340 mAh battery, originally shipping with Android 6.0 / EMUI 4.1 and upgradable to EMUI 5 and EMUI 8 on supported variants.

Over time, many users report serious software issues after updates—such as bootloops, “unknown model” bugs, failed Nougat/Oreo upgrades, random restarts, heavy lag, and battery drain—that often cannot be fully solved by simple factory resets and require clean stock firmware flashing to restore stability. Based on real user feedback and repair guides, common GR5 2017 / Honor 6X issues include:

• Bootloops and devices stuck on the Honor/Huawei logo after EMUI 5/8 OTA updates or failed SD‑card upgrades.
• “Unknown model” or “test‑keys” build number after custom ROMs or partial updates, breaking OTA and SafetyNet.
• Battery draining much faster than expected, device warming up, and random shutdowns on older batteries.
• System lag, app installation failures, Play Store errors, and crashes in heavy apps or games.
• Network issues like SIM not detected, unstable mobile data, or call/SMS problems; some units lose IMEI after bad flashes.

The official firmware packages listed below help by:

• Reinstalling clean EMUI 4.1 / 5.0 / 5.0.1 / 5.0.3 / 5.0.4 / 8.0 system images to fix bootloops, “unknown model” bugs and corrupted updates.
• Restoring correct regional CUST (C10, C185, C636, C675, C730, C752, etc.) so OTA updates and features work properly again.
• Improving stability, performance, and battery behavior compared to broken or heavily modified firmware.
• Unbricking devices stuck after failed Nougat/Oreo upgrades and reviving phones that only boot into eRecovery or Fastboot.
• Providing board‑software images for deep‑level repairs on BLN‑AL10/L24/L41/L42 when normal dload flashing is not enough.

Huawei GR5 2017 / Honor 6X Firmware Details

Download Official Firmware for Huawei GR5 2017 / Honor 6X (Berlin BLN & KII‑L21)

Flashing Requirements

Before You Begin ⚙️

• 💾 Backup Data: Flashing will erase apps, messages, photos, and internal storage. Back up to a PC, SD card, or cloud first.
• 🔋 Charge Battery: Ensure at least 50–60% battery to avoid shutdown during flashing.
• 💻 Use a PC & SD Card: You will need a Windows PC for extracting files and a quality microSD card (8–32 GB, FAT32) for dload.
• 🧩 Correct Drivers: Install Huawei USB drivers or HiSuite so your PC can recognize the phone in recovery/fastboot modes.
• 📦 Extract Firmware: Unzip or unrar the downloaded package; for dload you need the UPDATE.APP or dload folder content.
• 🆔 Match Model & CUST: Double‑check Settings → About phone (if accessible) or back‑label for exact model and CUST (C10, C185, C636, C675, etc.).

How to Flash the Firmware

📱 Quick Flashing Guides

Method 1: SD‑Card Dload (Most BLN & KII‑L21 Dload Files)

1. Prepare SD Card: Format a microSD card as FAT32. Create a folder named de>dload in the root directory.
2. Copy Firmware: From the extracted firmware, copy the de>UPDATE.APP (or full dload content) into the de>dload folder.
3. Insert & Power Off: Insert the SD card into your Honor 6X / GR5 2017 or GR5 (KII‑L21) and power the phone off completely.
4. 3‑Button Upgrade: Hold Volume Up + Volume Down + Power together until the update screen appears, then release. The phone will search the SD card and start flashing automatically.
5. Wait & Reboot: Do not interrupt. When progress reaches 100% the device will reboot. First boot after flashing can take 5–10 minutes.

For a detailed, step‑by‑step EMUI dload guide with screenshots, use: Full Tutorial: How to Flash Stock Firmware on Huawei via SD Card (dload)

Method 2: Huawei Smartphone Multi Download / Service Tools (Board Firmware)

1. Install Huawei Smartphone Multi Download Software and Huawei drivers on your PC.
2. Extract the board or full firmware package and load the correct configuration/XML inside the tool.
3. Power off the device. Some deep‑brick cases require test‑point or special key combinations to enter download mode.
4. Connect the phone to your PC via USB and start flashing from the tool interface.
5. Wait until the tool reports success, then disconnect and boot the phone.

For step‑by‑step instructions: Full Guide: Huawei Smartphone Multi Download Software

Method 3: OTA Zip Sideload (Some 8.0.0.x OTA Files)

1. Ensure you are on the correct base EMUI 5 build required by the OTA file.
2. Copy the OTA.zip to your SD card or internal storage (do not extract).
3. Boot into recovery (Volume Up + Power) and select Apply update or Install from SD/USB.
4. Choose the OTA.zip and confirm. The system will patch existing firmware to EMUI 8.0.
5. Reboot once the installation completes.

For generic OTA sideloading on Android, see: OTA Sideload: Install Stock Firmware on Android

Frequently Asked Questions (FAQs)

What problems can these GR5 2017 / Honor 6X firmwares fix?

They can fix bootloops after failed Nougat/Oreo OTAs, eRecovery loops, “unknown model” or test‑keys builds, severe lag, app crashes, installation errors, battery drain caused by corrupted system files, and many network/SIM detection issues.

How do I choose the correct file for my BLN or KII device?

Check your model (BLN‑L21/L22/L23/AL10/AL20/AL30/TL00/TL10 or KII‑L21) and CUST code (C10, C185, C636, C675, C730, C752, etc.) in Settings → About phone (if bootable) or from the box/back label. Only flash firmware where both model and CUST match perfectly; otherwise you risk hard‑bricking the device.

Can I upgrade directly from EMUI 4.1 to EMUI 8.0 on Honor 6X?

No, you must usually go stepwise: EMUI 4.1 (Android 6.0) → EMUI 5.x (Android 7.0) using the correct dload firmware, then apply the EMUI 8.0 full or OTA packages designed for your specific Chinese BLN‑AL/TL variant. Skipping steps or mixing regions can cause bootloops.

What if my GR5 2017 / Honor 6X is totally dead or not detected?

First, try SD‑card dload with a matching full firmware. If the device is still not detected, you may need board software plus professional tools (test‑point, Huawei service boxes, or local repair shops) to recover the boot chain, especially for BLN‑L24/L41/L42 or AL10 board packages.

Why does my phone show “unknown model” after flashing custom ROMs or wrong firmware?

This happens when OEMINFO and product data are corrupted or mismatched. Flashing the correct UPDATE.APP that matches your original BLN model and region (as described in Honor 6X repair guides) usually restores the proper model name and build number.

Can I use Qualcomm or SP Flash Tool on these devices?

No. The Honor 6X / GR5 2017 (BLN series) use HiSilicon Kirin 655, not MediaTek, and standard tools are Huawei’s dload method, HiSuite, and Huawei Multi Download Software—not SP Flash Tool or Xiaomi/Qualcomm tools. The older GR5 KII‑L21 is Qualcomm‑based but still normally flashed via dload/HiSuite.

Why is the phone laggy or draining battery even after a clean flash?

Aging batteries, background apps, and newer apps targeting modern hardware can still stress this mid‑range Kirin 655 SoC. Check battery health, disable bloatware, reduce background sync, and keep to a stable EMUI build known to perform well for your region.

Is it safe to downgrade from EMUI 8.0 back to EMUI 5.0 or 4.1?

Downgrades are possible but risky. Use only official rollback/downgrade packages for your exact model and CUST when available. A wrong or incomplete downgrade can soft‑brick the device or break future updates.