default or selected kernelversion does not have config value CONFIG_IEEE1394_ETH1394.
Result is shown for kernelversion 5.4.229

IP networking over 1394 (experimental)

modulename: eth1394.ko

configname: CONFIG_IEEE1394_ETH1394

Linux Kernel Configuration
└─>Device Drivers
└─>IEEE 1394 (FireWire) support
└─>IP networking over 1394 (experimental)
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
This driver implements a functional majority of RFC 2734: IPv4 over
1394. It will provide IP connectivity with implementations of RFC
2734 found on other operating systems. It will not communicate with
older versions of this driver found in stock kernels prior to 2.6.3.
This driver is still considered experimental. It does not yet support
MCAP, therefore multicast support is significantly limited.

The module is called eth1394 although it does not emulate Ethernet.

NOTE:
eth1394 is superseded by the newer firewire-net driver. See
http://ieee1394.wiki.kernel.org/index.php/Juju_Migration for
further information on how to switch to the new FireWire drivers.

source code:

depends
CONFIG_EXPERIMENTAL
CONFIG_IEEE1394
CONFIG_INET
CONFIG_BROKEN or CONFIG_PCI