:component_file:`nvs_flash/nvs_partition_generator/nvs_partition_gen.py` utility is designed to help create a binary file, compatible with NVS architecture defined in :doc:`Non-Volatile Storage </api-reference/storage/nvs_flash>`, based on user provided key-value pairs in a CSV file.
Utility is ideally suited for generating a binary blob, containing data specific to ODM/OEM, which can be flashed externally at the time of device manufacturing. This helps manufacturers set unique value for various parameters for each device, e.g. serial number, while using same application firmware for all devices.
Supported values are: ``u8``, ``i8``, ``u16``, ``u32``, ``i32``, ``string``, ``hex2bin``, ``base64`` and ``binary``. This specifies how actual data values are encoded in the resultant binary file. Difference between ``string`` and ``binary`` encoding is that ``string`` data is terminated with a NULL character, whereas ``binary`` data is not.
..note:: Encoding and Value cells for ``namespace`` field type should be empty. Encoding and Value of ``namespace`` is fixed and isn't configurable. Any value in these cells are ignored.
..note:: First row of the CSV file should always be column header and isn't configurable.
Below is an example dump of such CSV file::
key,type,encoding,value <-- column header
namespace_name,namespace,, <-- First entry should be of type "namespace"
key1,data,u8,1
key2,file,string,/path/to/file
..note:: Make sure there are no spaces before and after ',' in CSV file.
NVS Entry and Namespace association
-----------------------------------
When a new namespace entry is encountered in the CSV file, each follow-up entries will be part of that namespace, until next namespace entry is found, in which case all the follow-up entries will be part of the new namespace.
..note:: First entry in a CSV file should always be ``namespace`` entry.
This utility allows you to create an enrypted binary file also. Encryption used is AES-XTS encryption. Refer to :ref:`nvs_encryption` for more details.
..note:: In encryption mode, this utility creates a binary file named `encryption_keys.bin` containing the encryption keys used. This binary file is compatible with NVS key-partition structure. Refer to :ref:`nvs_key_partition` for more details.
You can also provide the format version number while running this utility:
- Multipage Blob Support Enabled (v2)
- Multipage Blob Support Disabled (v1)
*Multipage Blob Support Enabled (v2):*
You can run the utility in this format by setting the version parameter to v2, as shown below.
- Utility doesn't check for duplicate keys and will write data pertaining to both keys. User needs to make sure keys are distinct.
- Once a new page is created, no data will be written in the space left in previous page. Fields in the CSV file need to be ordered in such a way so as to optimize memory.
