NVram

Manipulate Nonvolatile memory

NVram

Shortest form: nv.

Read or write bytes of a board NVRAM (an Atmel 24C64 I2C EEPROM on reference boards). nvram r <offset> <count> dumps bytes (Reading <n> bytes at address 0x…), nvram w <offset> <byte> writes one byte. r and w are matched on the first letter; all three words are required.

This is a utility for Broadcom reference boards. It talks to a named device in the SDK’s I2C device table, on the I2C bus of the switch chip itself. On a SONiC switch the platform’s fans, sensors, EEPROMs and optics are normally handled by the platform drivers on the CPU’s own I2C buses, so the device is usually missing and the command prints NVram: cannot open I2C device nvram0: ….

Unvalidated

drivshell> nvram r 0 16

Built-in help

Usages:
           nvram r [off] [nbytes]
               - show specified number of NVRAM bytes starting at offset.
           nvram w [off] [data]
               - write data byte to specified NVRAM offset.