Google’s Android backup is useful for supported apps, messages, contacts, and settings, but it is not a raw backup of EFS, NVRAM, or modem partitions. There is also no universal Android partition called efs: the right radio-identity data to preserve depends on the exact phone. Identify the partitions on your model, make a raw image only of confirmed targets, verify it, and keep it off the phone. Never restore identity data from another device.
What an EFS or IMEI backup actually contains
An IMEI is an identifier displayed by Android or the modem. A screenshot or written record can help you document the original number, but it cannot restore a damaged modem partition or its calibration data.
On some Samsung devices, efs is a partition associated with IMEI-related and radio data. Other devices may use names such as modemst1, modemst2, fsg, nvram, nvdata, persist, or vendor-specific structures. Contents differ by manufacturer, chipset, generation, and firmware; a raw image of one partition may contain identity-related information, calibration, certificates, MAC addresses, or other modem state. Android’s partition layout is device-specific, with vendor partitions beyond the common core layout (AOSP partition overview).
Accordingly, “backing up the IMEI” usually means documenting the number and preserving the relevant original radio-data partition or partitions—not copying a number into a file. A partition image is useful only if it is complete, valid, and restored to the same physical device.
Recommended Free Tools
#1 Best Overall
- Please note, this device does not support E-SIM; This 4G model is compatible with all GSM networks worldwide outside of the U.S. In the US, ONLY compatible with T-Mobile and their MVNO's (Metro and Standup). It will NOT work with other CDMA carriers, and it is also not compatible with their MVNO (Visible, Xfinity Mobile, US Mobile, Cricket Wireless, etc).
- Compatibility with certain third-party devices and accessibility accessories, including some hearing aids, may vary depending on manufacturer support, Bluetooth protocols, software compatibility, and regional firmware limitations. For additional hearing aid compatibility information, please refer to Samsung’s official support documentation.
- Camera: 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 50 MP, f/1.8, (wide), 1/2.76", 0.64µm, AF | 2 MP, f/2.4, (macro). Battery: 5000 mAh, non-removable | A power adapter is NOT included.
Before you begin
Gather the details and access needed for your exact model before attempting a raw backup. Do not unlock a bootloader just to try a generic command without first protecting your ordinary files: unlocking commonly wipes user data on many devices.
- Exact model number and regional variant, plus Android version, firmware/build number, and current baseband version.
- Current IMEI or IMEIs and serial number, recorded privately. Do not post them publicly.
- Whether the bootloader is unlocked, whether working root is available, and whether a compatible custom recovery exists.
- A computer with working ADB/fastboot, a reliable USB cable, enough free storage, and a second backup location.
- A charged battery and a plan to store the image securely. Treat radio-partition images as sensitive, device-unique data; encrypt an offline copy if practical.
Ordinary ADB access does not imply permission to read protected partitions. A locked, unrooted production phone may deny access. Android 10 added restrictions on apps’ access to IMEI and serial-number data, and compatibility requirements also limit ordinary identifier access (Android identifier guidance; Android 11 compatibility definition).
Record the phone’s state and discover its partitions
Connect the phone with USB debugging enabled and confirm that ADB sees it. These commands collect model/build details and, if root works, list block-device symlinks. The common /dev/block/bootdevice/by-name path is not guaranteed.
adb devices
adb shell getprop ro.product.model
adb shell getprop ro.build.fingerprint
adb shell getprop ro.boot.slot_suffix
adb shell su -c 'ls -l /dev/block/bootdevice/by-name'If that directory is unavailable, a cautious discovery command is:
Do these 3 things before closing this tab:
1Scan for outdated or missing drivers - takes under a minute2Repair Windows errors before they cause bigger problems3Fix the driver behind crashes, sound loss and screen glitchesadb shell su -c 'find /dev/block -type l 2>/dev/null | sort'su requires a functioning root implementation. The device’s own listing—not a tutorial for a similar-looking phone—must establish the valid partition path. Stop if the expected name is absent, access is denied, or several similar partitions appear and you cannot determine which one is correct. Record the active slot shown by ro.boot.slot_suffix, but do not assume radio partitions have slot-specific copies; the listing and device documentation govern.
Rank #2
- YOUR CONTENT, SUPER SMOOTH: The ultra-clear 6.7" FHD+ Super AMOLED display of Galaxy A17 5G helps bring your content to life, whether you're scrolling through recipes or video chatting with loved ones.¹
- LIVE FAST. CHARGE FASTER: Focus more on the moment and less on your battery percentage with Galaxy A17 5G. Super Fast Charging powers up your battery so you can get back to life sooner.²
- MEMORIES MADE PICTURE PERFECT: Capture every angle in stunning clarity, from wide family photos to close-ups of friends, with the triple-lens camera on Galaxy A17 5G.
- NEED MORE STORAGE? WE HAVE YOU COVERED: With an improved 2TB of expandable storage, Galaxy A17 5G makes it easy to keep cherished photos, videos and important files readily accessible whenever you need them.³
- BUILT TO LAST: With an improved IP54 rating, Galaxy A17 5G is even more durable than before.⁴ It’s built to resist splashes and dust and comes with a stronger yet slimmer Gorilla Glass Victus front and Glass Fiber Reinforced Polymer back.
Modern layouts add another reason not to generalize old commands. Dynamic partitions can create, resize, and remove logical partitions inside super during updates, while vendor-specific partitions may remain outside that set (AOSP dynamic partitions; AOSP implementation details). This does not make super, system, or vendor a substitute for radio identity storage.
Make a raw image with root and dd
Use this only as a template after confirming that the exact device exposes an efs partition at this path and you have permission to read it. It creates an image of the named block device; it does not prove that the image contains every item needed for cellular service.
adb shell su -c 'dd if=/dev/block/bootdevice/by-name/efs of=/sdcard/efs.img bs=4M'
adb pull /sdcard/efs.imgIf the device instead exposes confirmed Qualcomm-style partitions, the following is illustrative only:
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →adb shell su -c 'dd if=/dev/block/bootdevice/by-name/modemst1 of=/sdcard/modemst1.img bs=4M'
adb shell su -c 'dd if=/dev/block/bootdevice/by-name/modemst2 of=/sdcard/modemst2.img bs=4M'
adb pull /sdcard/modemst1.img
adb pull /sdcard/modemst2.imgFor a device that actually lists nvram, an illustrative command is:
adb shell su -c 'dd if=/dev/block/bootdevice/by-name/nvram of=/sdcard/nvram.img bs=4M'
adb pull /sdcard/nvram.imgDo not replace a name in these examples just because another phone’s guide uses it. A wrong input path may copy unrelated data; a wrong output path can overwrite critical storage.
Rank #3
- Carrier: This phone is locked to Tracfone, which means this device can only be used on the Tracfone wireless network. Tracfone plan required, activating is easy, just 3 steps.
- DISPLAY: Immersive viewing on a 6.7-inch super-bright 120Hz display with powerful stereo speakers and Bass Boost for cinematic entertainment.
- CAMERA SYSTEM: Advanced 50MP Quad Pixel camera captures sharp, detailed photos and videos in any lighting condition
- PERFORMANCE: Lightning-fast 5G connectivity paired with a powerful processor and RAM Boost for smooth multitasking.
- BATTERY LIFE: Long-lasting 5000mAh battery with TurboPower charging technology delivers hours of power in minutes.
Use TWRP only if it explicitly exposes the relevant partition
On a device with compatible TWRP, boot into recovery, choose Backup, inspect the available partition list, and select EFS or the device-specific radio partitions only if they are explicitly listed. Choose external storage when available, run the backup, then copy the complete backup directory—including its metadata and logs—to a computer.
Do not assume an ordinary TWRP backup contains EFS: TWRP says its default selection is generally system, data, and boot (TWRP backup guidance). Nor does selecting data guarantee that all internal storage is included; TWRP documents exclusions from /data (TWRP backup exclusions).
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Recovery availability and layout vary. Some modern devices integrate recovery resources with boot-related partitions rather than using a conventional standalone recovery partition (AOSP vendor boot partitions; AOSP generic boot). Use recovery instructions only for a build compatible with the exact model.
Verify and protect the backup
A command returning to the prompt is not proof of a valid image. On the computer, check that the file exists and calculate its SHA-256 checksum:
ls -lh efs.img
sha256sum efs.imgOn macOS, use shasum -a 256 efs.img; in Windows PowerShell, use Get-FileHash .efs.img -Algorithm SHA256. If you take a second image without changing the device, compare hashes with sha256sum efs.img efs-second.img. Different hashes do not automatically prove corruption—the data could have changed or the captures may differ in conditions. Repeat from recovery or a quiescent state, confirm the input path, and inspect output for errors such as Permission denied, No such file, or Input/output error. Do not restore an image merely because a file exists.
Rank #4
- YOUR CONTENT, SUPER SMOOTH: The ultra-clear 6.7" FHD+ Super AMOLED display of Galaxy A17 5G helps bring your content to life, whether you're scrolling through recipes or video chatting with loved ones.¹
- LIVE FAST. CHARGE FASTER: Focus more on the moment and less on your battery percentage with Galaxy A17 5G. Super Fast Charging powers up your battery so you can get back to life sooner.²
- MEMORIES MADE PICTURE PERFECT: Capture every angle in stunning clarity, from wide family photos to close-ups of friends, with the triple-lens camera on Galaxy A17 5G.
- NEED MORE STORAGE? WE HAVE YOU COVERED: With an improved 2TB of expandable storage, Galaxy A17 5G makes it easy to keep cherished photos, videos and important files readily accessible whenever you need them.³
- BUILT TO LAST: With an improved IP54 rating, Galaxy A17 5G is even more durable than before.⁴ It’s built to resist splashes and dust and comes with a stronger yet slimmer Gorilla Glass Victus front and Glass Fiber Reinforced Polymer back.
Keep the image, checksum, and a small inventory together. Partition size has no universal correct value; investigate an unexpected size rather than guessing or restoring it.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Model:
Variant:
Serial:
Build fingerprint:
Android version:
Baseband version:
IMEI 1:
IMEI 2:
Partition path:
Backup date:
SHA-256:Copy the backup to at least one location off the phone and preferably a second, offline or encrypted location. Keep the IMEI record and image private; neither should be shared publicly.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Restore only the original image to the same phone
Restoration is a high-risk operation, not a general cellular repair. Consider it only when the image came from that exact physical device, predates the fault, and matches the confirmed target partition and size. The phone must be in an appropriate root or recovery environment. Never write another phone’s EFS, NVRAM, modem-state, calibration, or identity data to this device, and do not use partition backups to alter or substitute an IMEI.
For a confirmed efs target and a verified image known to belong to the same phone, the following is only a generic template—not a universal repair recipe:
adb push efs.img /sdcard/efs.img
adb shell
su
dd if=/sdcard/efs.img of=/dev/block/bootdevice/by-name/efs bs=4M
sync
exit
exit
adb rebootDo not execute a restore until the target path, image provenance, partition size, and model have been independently confirmed. Paths can differ, access may be protected, and some phones require an OEM-specific service procedure or exact stock firmware. A raw image may not correct problems caused by baseband firmware, carrier configuration, secure hardware, certificates, or a hardware fault.
Best Value
- Charger NOT Included, 6.7" Super AMOLED FHD+, 90Hz Refresh Rate, 385 ppi, 800 nits (HBM), 1080x2340px, 5000mAh Battery
- 128GB, 4GB RAM, microSDXC, Exynos 1330 (5nm), Octa-Core, Mali-G68 MP2 or Mali-G57 MC2 GPU
- Rear Camera: 50MP, f/1.8 (wide) + 5MP, f/2.2 (ultrawide) + 2MP, f/2.4 (macro), LED flash, panorama, HDR; Front Camera: 13MP, f/2.0, Android 14, up to 6 major Android upgrades, One UI 6.1
- 3G: HSDPA 850/900/1700(AWS)/1900/2100; 4G LTE: 1/2/3/4/5/7/12/13/14/20/25/26/28/29/30/38/39/40/41/48/66/71, 5G: 2/5/25/41/66/71/77/78 SA/NSA/Sub6/mmWave - Nano-SIM + eSIM
- US Model – Global Connectivity – Compatible with Most GSM Carriers like T-Mobile, AT&T, MetroPCS, etc. Will Also work with CDMA Carriers Such as Verizon, Straight Talk.
Check function after reboot
- Check the displayed IMEI in Settings or with the device’s supported
*#06#dialer code. - Check baseband version and whether the SIM is detected.
- Test cellular registration, calls, SMS, and mobile data; test VoLTE where relevant.
- Check Wi-Fi and Bluetooth if the affected device-specific partition may also contain their calibration or MAC data.
If the phone still has no IMEI or baseband, stop flashing random files. Use the exact stock-firmware or service procedure for the model, or contact an authorized repair provider.
Troubleshoot common blockers
No efs partition appears
This is normal for many devices. Do not create an empty image or substitute a partition named in a guide for another model; identify the radio-storage layout for the exact variant.
The partition listing is empty or inaccessible
Possible causes include missing root, recovery permissions, a different by-name location, the partition not being exposed in the current boot mode, vendor-specific layout, or SELinux restrictions. Stop instead of guessing a raw block path.
The bootloader is locked
A locked device may block raw access. Unlocking may wipe user data, so first protect ordinary files and understand the manufacturer’s process; unlocking is not a guarantee that the radio partition will become readable.
The device has A/B slots or dynamic partitions
Record the active slot, but do not append _a or _b to a radio partition unless the actual listing confirms that variant. Dynamic partitions primarily describe the OS layout and do not identify the phone’s radio-data location.
The device is encrypted or the backup size looks unusual
Encryption of user data does not make a copy of /data equivalent to a modem-identity backup. TWRP’s ability to decrypt and expose data varies by device and recovery build. Likewise, there is no universal EFS image size; compare it with the confirmed partition and investigate mismatches.
The phone already has no IMEI or baseband
A new image may preserve the damaged state. Preserve any older backup, record symptoms and error messages, and avoid untrusted “IMEI repair” files. If the original data is unavailable, seek the model-specific manufacturer or authorized service route rather than writing guessed data.
What Google backup can—and cannot—preserve
Google’s documented Android backup covers supported apps and app data, contacts, call history, SMS/MMS, and device settings, but it is not documented as a raw EFS, NVRAM, modem, or IMEI-partition backup. Google also cautions that not every app can back up or restore all settings and data (Google Android backup details). Use it for ordinary user data, not as a substitute for a confirmed raw radio-partition image.
Free tools Windows power users keep installed
One-click scans. No signup required.
Quick Recap
Pre-modification checklist
- IMEI and baseband recorded privately.
- Exact model, variant, build, and active slot recorded.
- Relevant partition name and path confirmed on this device.
- Raw image or compatible recovery backup created without errors.
- Backup copied off the phone and SHA-256 recorded.
- Second secure copy stored, with model/build/date metadata.
- No image from another device will be used.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
