Upon further investigation, it appears the archlinuxarm kernel is not associating the ethaddr setting in uEnv.txt with the nsa310 ethernet adapter.
lspci -v
$this->bbcode_second_pass_code('', '...
00:01.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 03)
Subsystem: Realtek Semiconductor Co., Ltd. RTL8111/8168 PCI Express Gigabit Ethernet controller
Flags: bus master, fast devsel, latency 0, IRQ 9
I/O ports at 1000 [size=256]
Memory at e0014000 (64-bit, prefetchable) [size=4K]
Memory at e0010000 (64-bit, prefetchable) [size=16K]
[virtual] Expansion ROM at e0000000 [disabled] [size=64K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [70] Express Endpoint, MSI 01
Capabilities: [ac] MSI-X: Enable- Count=4 Masked-
Capabilities: [cc] Vital Product Data
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Virtual Channel
Capabilities: [160] Device Serial Number 00-00-00-00-00-00-00-00
Kernel driver in use: r8169')
dmesg | grep r8169
$this->bbcode_second_pass_code('', '[ 16.875336] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
[ 16.881012] r8169 0000:00:01.0: enabling device (0140 -> 0143)
[ 16.887664] r8169 0000:00:01.0 eth0: RTL8168d/8111d at 0xd09c0000, 00:00:00:00:00:30, XID 083000c0 IRQ 9
[ 16.897252] r8169 0000:00:01.0 eth0: jumbo features [frames: 9200 bytes, tx checksumming: ko]
[ 25.167669] r8169 0000:00:01.0 enp0s1: renamed from eth0')
ip link
$this->bbcode_second_pass_code('', '1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp0s1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
link/ether 00:00:00:00:00:30 brd ff:ff:ff:ff:ff:ff')