AirPrime and HL7548 AT Commands Interface Guide Rev10 0

Table Of Contents
4116303 Rev 10.0 August 10, 2017 267
14. NV Related Commands
14.1. Auto Generation of NV Backup Files
There are 3 NV partitions in flash used by the firmware:
Static Calibrated NV partition
Static Fixed NV partition
Dynamic NV partition
NV backup is per partition based, with one NV backup file per partition. These are labelled with <file
id>=0, 1, 2 in the NV log and by firmware design.
The firmware automatically generates NV backup files from existing NV data at ~8 seconds after boot
if one of the following conditions are met:
NV backup of a partition does not exist, or it has been corrupted unexpectedly
NV backup files exist, but the firmware version has changed while IMEI has not changed, in
comparison to the records in the backup file
NV backup files exist, but the firmware version has changed and a valid IMEI has been
updated, in comparison to the records in the backup file
An automatic backup file generation is notified with +NVBU_IND with <status>=0 on all AT ports.
14.2. Auto Recovery from Backup NV Files
NV recovery is automatically done if an NV corruption is detected during NV initialization at boot.
The firmware automatically recovers NV data from available NV backups when one or more NV items
are corrupted. This is notified with +NVBU_IND with <status>=3 on all AT ports.
Manual NV data restores all data from backup file to the original NV partition.
The firmware will try to recover corrupted or missing NV data items instead of all NV data items
(partial restore) if possible; otherwise, the firmware restores all NV data items (full restore).
If the firmware crashes with 10 consecutive loops and a full restore has not been performed before,
the firmware performs a full restore of all NV data items. Only consecutive crashes that happened
within 8 seconds after the module boots is counted for this reset loop detection.
14.3. +NVBU: NV Backup Status and Control
HL7518 and HL7548
Test command
Syntax
AT+NVBU=?
Response
+NVBU: (0-2)
OK