Enable DIAG Mode on Samsung
Samsung is the easiest platform for Qualcomm DIAG activation. The dialer code *#0808# opens a native USB mode selector that enables DIAG without root or bootloader unlock.
Last verified 2026-04-15 on One UI 6.x and 7.x Qualcomm SKUs
Method : dialer code (no root)
- Open the phone dialer
- Enter
*#0808# - The USB Settings menu opens automatically
- Select DM+ACM+ADB (DIAG + serial + ADB)
- Press Back or OK to apply
- Connect USB to your host computer
Supported models
- Galaxy S20 / S21 / S22 / S23 / S24 / S25 (Qualcomm variants)
- Galaxy Note 10 / Note 20 Ultra (Qualcomm)
- Galaxy Z Fold 3 / 4 / 5 / 6 (Qualcomm global)
- Galaxy Z Flip 3 / 4 / 5 / 6 (Qualcomm global)
- Galaxy A74 / A75 Qualcomm variants (some regions)
Europe variants are typically Exynos and do NOT expose Qualcomm DIAG. Check the SoC in Settings > About phone.
Expected USB composite
After *#0808# selection:
Samsung VID: 04E8
PID: 6860 (DM + ACM + ADB)
Interfaces:
Interface 0: DIAG (Qualcomm)
Interface 1: MODEM / ACM
Interface 2: ADB
Interface 3: Optional NMEA Use HiCellTek without DIAG
HiCellTek RF Monitor reads RSRP, RSRQ, SINR, PCI, ARFCN, band, cell ID, neighbors, throughput on any Samsung (including Exynos) through the standard Android Telephony API. No *#0808#, no root, no bootloader unlock.
Frequently asked questions
Does *#0808# work on One UI 7?
Yes on Qualcomm SKUs (US, Korea, some MEA variants). One UI 7 preserves the USB configuration menu accessible through the dialer code.
Do I need root on Samsung?
No for the dialer code method. The engineering menu lets you switch USB mode to DM+ACM+ADB without root privileges.
Which Samsung models work?
Galaxy S20 to S25 series, Note series (until Note 20 Ultra), Z Fold/Flip with Qualcomm. Exynos variants (mostly Europe) do not expose Qualcomm DIAG.
How to identify Qualcomm vs Exynos?
Check Settings > About phone > Hardware information or the model number suffix. SM-G99x variants with /DS suffix are typically Exynos in Europe. USA and Korea versions tend to be Qualcomm.
What USB mode should I select?
DM+ACM+ADB (for DIAG + serial + ADB) or DM+MODEM+ADB (with AT command port). The exact naming depends on the firmware version.
Does it survive a One UI update?
The USB config may reset after an OTA. Re-run *#0808# after each major update.