“Room HP”: Myth, Misnomer, and Machine Code — A Firmware Engineer’s Deconstruction of Indonesia’s Most Dangerous Urban Legend in Android Repair
The phrase “Room HP” has no definition in Android’s source code, Qualcomm’s bootloader specs, or MediaTek’s engineering manuals. Yet in Indonesian repair shops, it wields near-mythical power — blamed for IMEI loss, bricked devices, and FRP loops. In this deep technical analysis, Riz.Net — an ATEI-certified firmware lab — dissects where the myth originates, maps it to real partitions in AOSP/Qualcomm/MTK documentation, and reveals why conflating marketing jargon with machine state risks irreversible hardware-level corruption.
There is no room partition in Android. There is no room.img. You will not find #define PARTITION_ROOM in AOSP’s bootloader/lk/platform/msm_shared/partition.h.
Yet — across Telegram groups, YouTube tutorials, and repair tables in Tanah Abang — technicians confidently say: “HP-nya kehapus room!” “Room-nya corrupt, harus inject ulang.” “Room tidak cocok, IMEI hilang.”
This isn’t just terminology drift — it’s a semantic collapse between physical flash layout and operational folklore.
At Riz.Net, we’ve recovered 127 devices in 2025 alone due to “room-related interventions” — 91% of which involved flashing modem.img from a different device variant, or zeroing persist without understanding its cryptographic binding to the secure boot chain.
Let’s fix the language — before more devices die to a myth.
🔬 Part I: What “Room HP” Actually Maps To — Verified Against Official Docs “Room HP” (Local Term) AOSP Partition Qualcomm SecTools Name MediaTek Scatter Entry Physical Risk Level “Room Modem” modem MODEM, MPSS modem, md1img 🔴 Critical — contains calibrated RF parameters, IMEI, baseband NV items “Room Boot” abl, xbl, xbl_config ABL, XBL, XBLCONFIG preloader, lk, tee1, tee2 🔴 Permanent brick risk — hash-locked to SoC fuses “Room Security” tz, hyp, keymaster, avbmeta TZ, HYP, KM, VB tee1, tee2, sec1, sec2, vbmeta 🔴 Security downgrade — disables Verified Boot, enables arbitrary code exec “Room IMEI/EFS” efs, persist EFS, PERSIST nvram, protect1, protect2 🟠 High — contains NV items (IMEI, MAC, calibration), but reconstructable with OEM tools (e.g., QPST/QXDM) “Room FRP” frp FRP frp 🟠 Medium — token storage; wipe = FRP lock, but recoverable with factory auth ✅ Source Verification:
AOSP: partition_list.h + Core Partition Docs Qualcomm: secboot_partition_list.xml (requires NDA login, but structure public via leaked 80-NH767-1) MediaTek: scatter_file_format.md (open-source reference implementation) ⚙️ Part II: Why “Room” Isn’t Just Wrong — It’s Dangerous ❌ Misconception #1: “Room = Backup yang Cukup untuk Restore Semua” Reality:
Backing up only modem.img ≠ backup IMEI. IMEI is stored in NV items inside modem, but also backed by checksums in persist and signed headers in vbmeta. If vbmeta hash no longer matches modem (e.g., after reflash), Qualcomm’s Secure Boot Chain will reject boot — even if IMEI bytes are intact. 🔬 Forensic case: Xiaomi Redmi Note 12 (Snapdragon 4 Gen 2) — modem.img restored, but vbmeta untouched → bootloop with SECURE_DEVICE_ERROR. ❌ Misconception #2: “Room bisa di-copy dari HP sejenis” Reality:
Even devices with same model number (e.g., SM-A145F) may have: Different RF calibration (modem’s efs/nv/68000/), tuned per factory batch Unique fuse-derived keys in tz (Trusted Execution Environment) Region-locked abl (e.g., ABL_IN vs ABL_EU) MediaTek’s Download Agent (DA) validates chip UID + scatter checksum before flashing preloader. Mismatch = permanent S-Boot lock. ❌ Misconception #3: “Room rusak = butuh inject ulang room” Reality:
Symptoms like “no signal”, “IMEI null”, or “emergency calls only” are symptoms, not root causes. Example: persist corruption → modem fails to initialize → reports “no baseband” → user blames “room modem”. Real fix: fastboot flash persist persist_clean.img (not reflashing entire modem). Diagnosa benar memerlukan: QXDM log (adb shell dmesg | grep -i "qmi|ril|modem") Qualcomm Diag Port (AT+QGETIMEI?, AT+QCFG="usbnet",1) Mediatek Meta Mode (AT+EGMR=1,7, — only works if NVRAM unlockable) 📦 Part III: Safe “Room-Level” Operations — Verified Protocols ✅ A. Backup Only What Matters — Minimal & Verified 🔹 For Qualcomm (via EDL + QFIL):
- MODEM → modem.img
- EFS → efs.img
- PERSIST → persist.img
- ABL → abl.img (⚠️ only if replacing bootloader!)
🔹 For MediaTek (SP Flash Tool Readback):
Region | Scatter Name | Why ----------------|--------------|----------------------------- Modem NV | nvram | Contains IMEI, BT/WiFi MAC Calibration | protect1 | RF tuning (Tx power, freq offset) Persistent data | protect2 | Sensor cal, battery age Preloader hash | preloader | ONLY if reflashing full firmware
📌 Golden Rule: Never use raw address (0x1E00000) — use logical partition names. Physical offsets change per device (e.g., Dimensity 7050 vs 9200).
✅ B. Restoration Protocol (When You Must Flash)
Step Action Validation 1 Flash abl / preloader first Check dmesg: XBL verified by SECBOOT 2 Flash tz, hyp, keymaster Verify fastboot getvar secure → yes 3 Flash modem Check /dev/block/platform/soc/1d84000.ufshc/by-name/modem exists 4 Restore persist & efs Run adb shell getprop gsm.serial → returns non-empty 5 Rebuild AVB: fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img Only for dev — never ship like this ⚠️ DO NOT:
Flash modem without matching modemst1/modemst2 (Qualcomm) Use --force in fastboot on vbmeta unless you own the signing key Assume nvram backup = IMEI backup — always verify with *#06# post-flash 🧪 Part IV: Diagnosing “Room Failure” — Without Guessing Use this forensic flowchart (based on 200+ Riz.Net case logs):
graph TD A[No Signal / IMEI Null] --> B{Can enter Recovery?} B -->|Yes| C[Check getprop | grep 'gsm|ril'] B -->|No| D[EDL / BROM Mode Required] C --> E[gsm.version.baseband = ?] E -->|empty| F[Modem not loaded → check dmesg for 'rpmh' or 'rpm' errors] E -->|valid but IMEI=0| G[Check /efs/imei or /nvram/md/NVRAM/NVD_IMEI] F --> H[ABL/TZ mismatch? → verify vbmeta hash] G --> I[Persist corruption? → restore protect1/2]
💡 Pro Tool: Use adb shell cat /proc/last_kmsg | grep -A5 -B5 'MPSS|MODEM' for crash context.
🛡️ Part V: When to Walk Away — And Call Riz.Net Some “room” issues are hardware-coupled and cannot be fixed by flashing:
Symptom Root Cause Fixable? ❌ “Qualcomm HS-USB QDLoader 9008” not detected EDL auth failure (OEM lock + fuse blow) Only with OEM signature (e.g., Xiaomi Auth Tool) ❌ Mediatek Preloader stuck at 0% DA signature mismatch (anti-rollback counter) Requires physical eMMC reball or OEM service ❌ IMEI returns after reboot, gone after power cycle NVRAM write failure (eMMC wear-out) Replace eMMC chip — software won’t help ❌ Baseband shows, but no registration (even on known-good SIM) RF front-end damage (PA, filter, antenna switch) Hardware repair — not firmware 🔧 Riz.Net’s Firmware Surgery Service (Jakarta Pusat):
Diagnostic Tier: Rp125.000 → includes QXDM log analysis, partition hash audit, IMEI validation Restore Tier: Rp220.000 → safe modem+persist restore with post-flash stability test EDL Recovery Tier: Rp299.000 → authorized OEM unlock (via partner tools), no data loss ✅ Garansi 30 hari ✅ Laporan teknis PDF (dengan screenshot fastboot getvar all, dmesg) ✅ Tidak perlu bongkar — kecuali kerusakan fisik terdeteksi
🎁 Bonus: Open-Source Toolkit for Ethical “Room” Work Scan QR via WhatsApp (+62 822-5766-0240) dan dapatkan:
📦 riznet-room-checker.sh — script otomatis untuk: bash 1234
fastboot getvar all | grep -E "secure|unlocked|version" ls -l /dev/block/platform/*/by-name/{modem,persist,efs} getprop | grep -E "gsm.baseband|ril." 📄 “Android Partition Cross-Reference Guide” (PDF 24 halaman): Mapping: Xiaomi NON-HLOS.bin ←→ AOSP modem ←→ Qualcomm MPSS Samsung modem.bin vs OPPO modem.img structure Cara baca nvram dengan mtkclient (open-source) 🔑 Kode promo: ROOM2025 → diskon 25% + gratis remote diagnosis 📅 Berlaku sampai 31 Desember 2025
🔚 Closing: The Path Forward — From Myth to Mastery “Room HP” is a symptom of a deeper gap: between grassroots repair culture and upstream engineering rigor.
We don’t seek to shame the term — we seek to elevate the practice.
The next generation of Indonesian technicians shouldn’t memorize “room” — they should understand why persist binds to the RPMB partition, how vbmeta enforces AVB 2.0 rollback protection, and when a “brick” is really a fuse state, not a file.
Because in firmware, there are no myths — only bits, signatures, and consequences.
📚 Referensi Resmi (Diverifikasi 2025): 🌐 AOSP: Core Partitions 🔒 Qualcomm: Secure Boot & Partition Signing (80-NH767-1 Rev.J) 📡 MediaTek: SP Flash Tool & Scatter File Spec 📱 Google: Android Verified Boot (AVB) 2.0 📍 Riz.Net Official ATEI-Certified Firmware & Hardware Lab | On-Site Jakarta | WhatsApp 24/7 📍 Jl. Melati No.10, Jakarta Pusat 🌐 https://riznet-official.vercel.app 📱 WhatsApp: +62 822-5766-0240
