BD_Security's complete EDL root guide

Source: [#423 p22 BD_Security · Feb 22, 2026]. Preserved here close to verbatim because it's a complete, self-contained workflow worth not paraphrasing.

Bottom line: root a RM10 Pro with the bootloader still locked, by flashing patched vbmeta_b + Magisk-patched init_boot_b via EDL/firehose directly. The bootloader never participates — it just boots what's on UFS, and AVB is disabled by the vbmeta flag patch.

Based on 26+ hours of debugging a bricked device. The most important lessons:

• Don't trust the 8-second window. The programmer is alive for ~8 s but you have to catch it in the first 2 s after USB re-enumeration. Clean 9008 via volume buttons gives that timing.
• The ZLP issue cost 10+ hours. Firehose with ZLPAwareHost="1" is strict — one ZLP at the end, not after every chunk.
• vbmeta is NOT optional — flashing modified init_boot without patching vbmeta to flags=0x02 gives "device is corrupt" every time.
• The programmer IS correct — devprg.melf from ZTE dump mode is a valid firehose programmer. Don't waste time hunting another one.

---

The problem this solves

Device stuck in ZTE MemoryDump Mode (VID 19D2/PID 0112) showing "Your device is corrupt and will not boot". Custom scripts fail with USB errors, programmer crashes, Sahara uploads succeed (38 chunks) but firehose never starts.

Critical discoveries

What DOESN'T work

• ZTE → SWITCH_MODE → 9008 transition (corrupts USB state, kills programmer)
• clear_halt() after Sahara DONE (hangs 6–8 s, misses programmer window)
• Reconnecting to the same handle after programmer starts (device disappears)
• Zero-Length Packet after every chunk (corrupts data)
• Using 1,2,3,4,5,6 in HELLO_RESP reserved bytes (causes mode mismatch)

What DOES work

1. Clean 9008 entry via volume buttons (bypass ZTE crash handler)
2. Exact Sahara protocol from edl_v5 (all-zero reserved bytes)
3. NO post-DONE delays — read immediately
4. Continuous data + ONE ZLP at the very end
5. Flash BOTH patched init_boot AND patched vbmeta
6. Direct 9008 entry = success. ZTE transition = failure.

The real insight

devprg.melf is a valid firehose programmer. Sahara uploads 38 chunks successfully every time with DONE_RSP status=0. The problem: after Sahara DONE the programmer:

1. Restarts the USB controller
2. Re-enumerates as a new 9008 device (max packet 512 → 1024)
3. Our old USB handle dies → Errno 19: No such device
4. Windows takes 60+ s to load drivers → programmer's 8-s watchdog fires → crash → back to ZTE dump

The "8-second window" is a myth — we were talking to a dead PBL handle, never the actual programmer.

Prerequisites

Hardware

• RM10 Pro (NX789J)
• USB-C data cable
• Windows PC (Linux/Mac can adapt)

Software

# Python 3.8+
pip install pyusb libusb

# bkerler/edl (optional but helpful)
git clone https://github.com/bkerler/edl
cd edl
pip install -r requirements.txt

Files

File	Source	Size
devprg.melf	extract via EDL / from ZTE dump mode	~1.6 MB
abl_b_dump.bin	backup of stock abl_b	1 MB
init_boot_b.img	stock from device or firmware	8 MB
vbmeta_b.img	stock from device or firmware	64 KB

Phase 1 — enter clean 9008

1. Unplug USB cable
2. Press and hold BOTH Volume Up + Volume Down
3. While holding, plug USB cable back in
4. Keep holding for 5–10 seconds
5. Device should appear as "Qualcomm HS-USB QDLoader 9008"

Verify on Windows:

Get-PnpDevice | Where-Object { $_.InstanceId -match "VID_05C6.*PID_9008" }
# Status OK, FriendlyName contains "9008"

This bypasses ZTE's crash handler, putting the SoC in clean PBL Sahara mode; the programmer stays alive ~8 s after loading.

Phase 2 — backup partitions

Partition layout (LUN 4, sector size 4096)

Partition	Start sector	Sectors	Size
xbl_b	184	15360	60 MB
abl_b	448832	256	1 MB
vbmeta_vendor_b	492584	16	64 KB
vbmeta_b	490260	16	64 KB
vbmeta_system_b	520120	16	64 KB
boot_b	683040	32768	128 MB
init_boot_b	686048	2048	8 MB

Critical addresses (Python)

VBMETA_B = {
    'lun': 4, 'start': 490260, 'sectors': 16, 'size': 65536
}
INIT_BOOT_B = {
    'lun': 4, 'start': 686048, 'sectors': 2048, 'size': 8388608
}

Phase 3 — patch vbmeta

def patch_vbmeta_flags(input_file, output_file):
    """Set AVB flags to 0x02 (verification disabled)."""
    with open(input_file, 'rb') as f:
        data = bytearray(f.read())
    # Flags at offset 0x0C, 4-byte LE: 00 00 00 00 → 02 00 00 00
    data[12:16] = b'\x02\x00\x00\x00'
    with open(output_file, 'wb') as f:
        f.write(data)

patch_vbmeta_flags("vbmeta_b_stock.img", "vbmeta_b_patched.img")

Verify:

avbtool info_image --image vbmeta_b_patched.img | grep Flags
# Flags: 2

hexdump -C -n 64 vbmeta_b_patched.img | head
# At offset 0x0C: 02 00 00 00

Phase 4 — Magisk-patch init_boot

1. Install Magisk APK
2. Copy stock init_boot_b.img to /sdcard/Download/
3. In Magisk app: Install → Select and Patch a File → choose the img
4. Pull /sdcard/Download/magisk_patched.img

Phase 5 — flash both in one EDL session

Working files in working directory:

• devprg.melf
• vbmeta_b_patched.img (64 KB)
• magisk_patched.img (8 MB)

The full working script — see source post for the complete root_redmagic.py (Sahara upload, firehose configure, firehose program for vbmeta_b then init_boot_b). The key constants:

LUN = 4
VBMETA_SECTOR    = 490260; VBMETA_SECTORS   = 16
INITBOOT_SECTOR  = 686048; INITBOOT_SECTORS = 2048

Configure XML:

<?xml version="1.0" encoding="UTF-8" ?>
<data><configure MemoryName="UFS" Verbose="0" AlwaysValidate="0"
                MaxDigestTableSizeInBytes="2048"
                MaxPayloadSizeToTargetInBytes="1048576"
                ZLPAwareHost="1" SkipStorageInit="0" SkipWrite="0" Oem="ZTE"/></data>

Program XML template (per partition):

<?xml version="1.0" ?>
<data><program SECTOR_SIZE_IN_BYTES="4096"
              num_partition_sectors="{num}" physical_partition_number="4"
              start_sector="{start}" filename="{name}"/></data>

Send-data loop: chunk size 64 KB over ep_out, then one empty write to send the ZLP, then wait for the final value="ACK" from firehose.

After both partitions ACK:

<?xml version="1.0" ?><data><power value="reset"/></data>

First boot 2–3 min — Magisk should appear.

Phase 6 — troubleshooting reference

Symptom	Cause	Fix
No 9008 device	Vol-button method failed	Drain battery, retry. Last resort: EDL test point.
Sahara not 38 chunks	Wrong programmer	Check devprg.melf size ~1.6 MB and b'configure' in binary
Configure NAK	ZTE→9008 transition, not clean	Re-enter via vol buttons
Flash succeeds but won't boot	vbmeta not patched, or wrong slot	Re-verify flags=0x02; check active slot via fastboot getvar current-slot
Stuck at "Your device is corrupt"	vbmeta verification still on	Re-flash patched vbmeta, check correct slot

FAQ excerpts

Is the bootloader unlocked after this?

No — this method bypasses the bootloader via EDL. The bootloader remains locked. Rooted with a locked bootloader is possible on Qualcomm devices via EDL.

Why doesn't ZTE→SWITCH_MODE work?

ZTE crash handler leaves USB dirty. After transition, programmer's USB reset creates a new device that Windows takes 60+ s to enumerate — programmer's 8-s watchdog fires first.

ZLP semantics?

Firehose with ZLPAwareHost="1" expects a ZLP after data transfers that are exact multiples of USB packet size. 8 MB is a multiple of 512/1024, so ZLP is required at end. Sending ZLP after every chunk corrupts data.

Will this work on other RM models?

Principles port, partition addresses don't. Dump GPT for your specific model first.

Why this matters even now (May 2026)

Even with the toolbox unlock available, BD_Security's procedure remains the canonical recovery path:

• Unbricks a phone stuck in MemoryDump
• Roots a phone where the user wants to keep the bootloader locked (SafetyNet / banking-app reasons)
• Documents the firehose protocol details that any future tooling will need