1. Backup current flash fully → current.bin
2. Run: spd_tool --info current.bin
→ Look for "NV region start: 0x..., size: 0x..."
3. Run: spd_tool --info backup.BKF
→ Compare NV sizes.
4. If different: Use hex editor to copy NV region from current.bin into backup.BKF
5. Disable strict NV check (if tool allows): spd_tool --force-nv-match
6. Re-flash with new composite binary.
If you must write the NV file, the tool may need to be configured to handle the write differently.
Version incompatibility is the #1 cause.
Pro tip: Keep a collection of 3-4 different tool versions. Try each. Many technicians report that moving from v5.1616 to v5.1628 alone fixes the BKF NV Error.
You have your SP Flash Tool ready, a scatter file loaded, and a firmware package that includes a .bin or .img file labeled BKF (backup) or NV (non‑volatile memory — your device’s unique IDs, IMEI, Wi‑Fi MAC, etc.).
You click Download, and bam — the tool stops with: spd flash tool bkf nv error
“BKF NV error”
or
“S_DL_PMT_ERR_NO_SPACE (0x1313)” with a BKF region mention.
Your phone / tablet refuses to boot normally, or you lose IMEI. Sound familiar? Let’s fix it.
Most engineers would expect a generic verify failed error. The inclusion of NV is interesting: If you must write the NV file, the
The SPD Flash Tool BKF NV Error is not a death sentence for your device. It is primarily a protective mechanism gone awry, triggered by version mismatches, corrupt backups, or improper settings. By systematically changing the NV operation mode, switching tool versions, or (as a last resort) formatting the NV region, you can successfully flash your Unisoc/Spreadtrum device.
Always remember: The BKF partition holds your device's digital identity. When you bypass or format it, be prepared to restore IMEIs and calibration data. With the steps outlined in this guide, you can turn that frustrating red error message into a successful green "Pass."
Key Takeaway: Next time you see "BKF NV Error," don't panic. Change the NV operation to "Restore Only" – nine times out of ten, that’s the fix. Pro tip: Keep a collection of 3-4 different tool versions
Before proceeding, ensure you have:
To understand the error, we must disassemble the name: