Something else odd that was occuring before but now much more promenant since I've added ~3TB of data to the drive, is that it disables (nearly?) most ethernet devices it is plugged into while booting up, and takes the good part of an hour to settle down before being accessible again to the network.
This is the kernel and system logs after finally getting on the network:
[ 0.000000] Linux version 5.15.137 (builder@buildhost) (mipsel-openwrt-linux-musl-gcc (OpenWrt GCC 12.3.0 r23630-842932a63d) 12.3.0, GNU ld (GNU Binutils) 2.40.0) #0 Tue Nov 14 13:38:11 2023
[ 0.000000] Board has DDR2
[ 0.000000] Analog PMU set to hw control
[ 0.000000] Digital PMU set to hw control
[ 0.000000] SoC Type: MediaTek MT7620A ver:2 eco:6
[ 0.000000] printk: bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 00019650 (MIPS 24KEc)
[ 0.000000] MIPS: machine is Kimax U35WF
[ 0.000000] Initrd not found or empty - disabling initrd
[ 0.000000] Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
[ 0.000000] Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes
[ 0.000000] Zone ranges:
[ 0.000000] Normal [mem 0x0000000000000000-0x0000000007ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x0000000007ffffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000007ffffff]
[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.000000] pcpu-alloc: [0] 0
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 32480
[ 0.000000] Kernel command line: console=ttyS0,57600 rootfstype=squashfs,jffs2
[ 0.000000] Dentry cache hash table entries: 16384 (order: 4, 65536 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 8192 (order: 3, 32768 bytes, linear)
[ 0.000000] Writing ErrCtl register=00000000
[ 0.000000] Readback ErrCtl register=00000000
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 120996K/131072K available (5929K kernel code, 608K rwdata, 740K rodata, 1224K init, 225K bss, 10076K reserved, 0K cma-reserved)
[ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] NR_IRQS: 256
[ 0.000000] CPU Clock: 580MHz
[ 0.000000] clocksource: systick: mask: 0xffff max_cycles: 0xffff, max_idle_ns: 583261500 ns
[ 0.000000] systick: enable autosleep mode
[ 0.000000] systick: running - mult: 214748, shift: 32
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6590553264 ns
[ 0.000002] sched_clock: 32 bits at 290MHz, resolution 3ns, wraps every 7405115902ns
[ 0.015584] Calibrating delay loop... 385.84 BogoMIPS (lpj=1929216)
[ 0.087794] pid_max: default: 32768 minimum: 301
[ 0.098151] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.112586] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.136515] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.156027] futex hash table entries: 256 (order: -1, 3072 bytes, linear)
[ 0.169736] pinctrl core: initialized pinctrl subsystem
[ 0.181865] NET: Registered PF_NETLINK/PF_ROUTE protocol family
[ 0.194299] thermal_sys: Registered thermal governor 'step_wise'
[ 0.210638] rt2880_gpio 10000600.gpio: registering 24 gpios
[ 0.233606] rt2880_gpio 10000600.gpio: registering 24 irq handlers
[ 0.246395] rt2880_gpio 10000660.gpio: registering 32 gpios
[ 0.257441] rt2880_gpio 10000660.gpio: registering 32 irq handlers
[ 0.270102] rt2880_gpio 10000688.gpio: registering 1 gpios
[ 0.280962] rt2880_gpio 10000688.gpio: registering 1 irq handlers
[ 0.295886] clocksource: Switched to clocksource systick
[ 0.308332] NET: Registered PF_INET protocol family
[ 0.318288] IP idents hash table entries: 2048 (order: 2, 16384 bytes, linear)
[ 0.333792] tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 4096 bytes, linear)
[ 0.350388] Table-perturb hash table entries: 65536 (order: 6, 262144 bytes, linear)
[ 0.365710] TCP established hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.380952] TCP bind hash table entries: 1024 (order: 0, 4096 bytes, linear)
[ 0.394972] TCP: Hash tables configured (established 1024 bind 1024)
[ 0.407809] UDP hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 0.420750] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes, linear)
[ 0.435066] NET: Registered PF_UNIX/PF_LOCAL protocol family
[ 0.446311] PCI: CLS 0 bytes, default 32
[ 0.454272] rt-timer 10000100.timer: maximum frequency is 1220Hz
[ 0.471353] workingset: timestamp_bits=14 max_order=15 bucket_order=1
[ 0.491625] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.503160] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.524355] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
[ 0.542534] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[ 0.558826] printk: console [ttyS0] disabled
[ 0.567352] 10000c00.uartlite: ttyS0 at MMIO 0x10000c00 (irq = 20, base_baud = 2500000) is a Palmchip BK-3103
[ 0.587002] printk: console [ttyS0] enabled
[ 0.603576] printk: bootconsole [early0] disabled
[ 0.645404] spi spi0.0: force spi mode3
[ 0.654445] spi-nor spi0.0: mx25l12805d (16384 Kbytes)
[ 0.664849] 4 fixed-partitions partitions found on MTD device spi0.0
[ 0.677591] OF: Bad cell count for /palmbus@10000000/spi@b00/flash@0/partitions
[ 0.692221] OF: Bad cell count for /palmbus@10000000/spi@b00/flash@0/partitions
[ 0.707357] OF: Bad cell count for /palmbus@10000000/spi@b00/flash@0/partitions
[ 0.722031] OF: Bad cell count for /palmbus@10000000/spi@b00/flash@0/partitions
[ 0.736876] Creating 4 MTD partitions on "spi0.0":
[ 0.746541] 0x000000000000-0x000000030000 : "u-boot"
[ 0.760231] 0x000000030000-0x000000040000 : "u-boot-env"
[ 0.772349] 0x000000040000-0x000000050000 : "factory"
[ 0.786040] 0x000000050000-0x000001000000 : "firmware"
[ 0.798068] 2 uimage-fw partitions found on MTD device firmware
[ 0.809966] Creating 2 MTD partitions on "firmware":
[ 0.819932] 0x000000000000-0x000000230249 : "kernel"
[ 0.829846] mtd: partition "kernel" doesn't end on an erase/write block -- force read-only
[ 0.849591] 0x000000230249-0x000000fb0000 : "rootfs"
[ 0.859586] mtd: partition "rootfs" doesn't start on an erase/write block boundary -- force read-only
[ 0.879353] mtd: setting mtd5 (rootfs) as root device
[ 0.890728] 1 squashfs-split partitions found on MTD device rootfs
[ 0.903232] 0x000000750000-0x000000fb0000 : "rootfs_data"
[ 0.946807] gsw: setting port4 to ephy mode
[ 0.955597] mtk_soc_eth 10100000.ethernet: no mdio-bus child node found
[ 0.968850] mtk_soc_eth 10100000.ethernet: mdio-bus disabled
[ 0.980364] mtk_soc_eth 10100000.ethernet: loaded mt7620 driver
[ 0.993087] mtk_soc_eth 10100000.ethernet eth0: mediatek frame engine at 0xb0100000, irq 5
[ 1.010477] rt2880_wdt 10000120.watchdog: Initialized
[ 1.022669] NET: Registered PF_INET6 protocol family
[ 1.040950] Segment Routing with IPv6
[ 1.048467] In-situ OAM (IOAM) with IPv6
[ 1.056481] NET: Registered PF_PACKET protocol family
[ 1.066660] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[ 1.092915] 8021q: 802.1Q VLAN Support v1.8
[ 1.126797] VFS: Mounted root (squashfs filesystem) readonly on device 31:5.
[ 1.147578] Freeing unused kernel image (initmem) memory: 1224K
[ 1.159410] This architecture does not have kernel memory protection.
[ 1.172260] Run /sbin/init as init process
[ 1.180423] with arguments:
[ 1.180430] /sbin/init
[ 1.180437] with environment:
[ 1.180444] HOME=/
[ 1.180450] TERM=linux
[ 2.606629] init: Console is alive
[ 2.614117] init: - watchdog -
[ 3.517585] mtk_soc_eth 10100000.ethernet eth0: port 4 link up (100Mbps/Full duplex)
[ 6.423560] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[ 6.589578] usbcore: registered new interface driver usbfs
[ 6.600771] usbcore: registered new interface driver hub
[ 6.611511] usbcore: registered new device driver usb
[ 6.679123] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 6.704754] SCSI subsystem initialized
[ 6.719906] fsl-ehci: Freescale EHCI Host controller driver
[ 6.734616] ehci-platform: EHCI generic platform driver
[ 6.755750] phy phy-usbphy.0: remote usb device wakeup disabled
[ 6.767590] phy phy-usbphy.0: UTMI 16bit 30MHz
[ 6.776451] ehci-platform 101c0000.ehci: EHCI Host Controller
[ 6.787945] ehci-platform 101c0000.ehci: new USB bus registered, assigned bus number 1
[ 6.803963] ehci-platform 101c0000.ehci: irq 26, io mem 0x101c0000
[ 6.826788] ehci-platform 101c0000.ehci: USB 2.0 started, EHCI 1.00
[ 6.840650] hub 1-0:1.0: USB hub found
[ 6.849173] hub 1-0:1.0: 1 port detected
[ 6.865910] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[ 6.880105] ohci-platform: OHCI generic platform driver
[ 6.891199] ohci-platform 101c1000.ohci: Generic Platform OHCI controller
[ 6.904834] ohci-platform 101c1000.ohci: new USB bus registered, assigned bus number 2
[ 6.920879] ohci-platform 101c1000.ohci: irq 26, io mem 0x101c1000
[ 6.960643] hub 2-0:1.0: USB hub found
[ 6.969242] hub 2-0:1.0: 1 port detected
[ 6.991262] usbcore: registered new interface driver usb-storage
[ 7.005117] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[ 7.024138] init: - preinit -
[ 7.149355] usb 1-1: new high-speed USB device number 2 using ehci-platform
[ 7.953927] hub 1-1:1.0: USB hub found
[ 8.338109] hub 1-1:1.0: 4 ports detected
[ 8.347137] random: procd: uninitialized urandom read (4 bytes read)
[ 8.829698] usb 1-1.4: new high-speed USB device number 3 using ehci-platform
[ 9.354757] usb-storage 1-1.4:1.0: USB Mass Storage device detected
[ 9.386440] scsi host0: usb-storage 1-1.4:1.0
[ 10.039115] random: jshn: uninitialized urandom read (4 bytes read)
[ 10.173445] random: jshn: uninitialized urandom read (4 bytes read)
[ 10.256865] random: jshn: uninitialized urandom read (4 bytes read)
[ 10.480492] scsi 0:0:0:0: Direct-Access ASMT 2115 0 PQ: 0 ANSI: 6
[ 10.520434] sd 0:0:0:0: [sda] Very big device. Trying to use READ CAPACITY(16).
[ 10.555933] sd 0:0:0:0: [sda] 31251759104 512-byte logical blocks: (16.0 TB/14.6 TiB)
[ 10.571651] sd 0:0:0:0: [sda] 4096-byte physical blocks
[ 10.609347] sd 0:0:0:0: [sda] Write Protect is off
[ 10.618949] sd 0:0:0:0: [sda] Mode Sense: 43 00 00 00
[ 10.629273] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 10.783421] sd 0:0:0:0: [sda] Attached SCSI disk
[ 11.046424] 8021q: adding VLAN 0 to HW filter on device eth0
[ 12.091175] mount_root: loading kmods from internal overlay
[ 12.151592] kmodloader: loading kernel modules from //etc/modules-boot.d/*
[ 12.172809] kmodloader: done loading kernel modules from //etc/modules-boot.d/*
[ 13.402297] jffs2: notice: (359) jffs2_build_xattr_subsystem: complete building xattr subsystem, 78 of xdatum (43 unchecked, 35 orphan) and 122 of xref (62 dead, 0 orphan) found.
[ 13.435307] block: attempting to load /tmp/jffs_cfg/upper/etc/config/fstab
[ 13.466785] block: extroot: not configured
[ 13.834715] jffs2: notice: (357) jffs2_build_xattr_subsystem: complete building xattr subsystem, 78 of xdatum (43 unchecked, 35 orphan) and 122 of xref (62 dead, 0 orphan) found.
[ 13.869591] mount_root: loading kmods from internal overlay
[ 13.928575] kmodloader: loading kernel modules from /tmp/overlay/upper/etc/modules-boot.d/*
[ 13.956263] kmodloader: done loading kernel modules from /tmp/overlay/upper/etc/modules-boot.d/*
[ 14.750394] block: attempting to load /tmp/jffs_cfg/upper/etc/config/fstab
[ 14.783381] block: extroot: not configured
[ 14.794788] mount_root: switching to jffs2 overlay
[ 15.066765] overlayfs: upper fs does not support tmpfile.
[ 15.087417] urandom-seed: Seeding with /etc/urandom.seed
[ 15.309167] procd: - early -
[ 15.315355] procd: - watchdog -
[ 16.331666] procd: - watchdog -
[ 16.345797] procd: - ubus -
[ 16.811163] random: ubusd: uninitialized urandom read (4 bytes read)
[ 16.827683] random: ubusd: uninitialized urandom read (4 bytes read)
[ 16.841245] random: ubusd: uninitialized urandom read (4 bytes read)
[ 16.970048] procd: - init -
[ 18.669455] random: jshn: uninitialized urandom read (4 bytes read)
[ 18.873296] random: ubusd: uninitialized urandom read (4 bytes read)
[ 18.886476] random: ubus: uninitialized urandom read (4 bytes read)
[ 19.982850] kmodloader: loading kernel modules from /etc/modules.d/*
[ 20.787997] zram: Added device: zram0
[ 20.892986] ksmbd: The ksmbd server is experimental, use at your own risk.
[ 20.965166] Loading modules backported from Linux version v6.1.24-0-g0102425ac76b
[ 20.980208] Backport generated by backports.git v5.15.92-1-44-gd6ea70fafd36
[ 22.342640] PPP generic driver version 2.4.2
[ 22.384687] NET: Registered PF_PPPOX protocol family
[ 22.530831] rt2800_wmac 10180000.wmac: loaded eeprom from mtd device "factory"
[ 22.545311] ieee80211 phy0: rt2x00_set_rt: Info - RT chipset 6352, rev 0500 detected
[ 22.560816] ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 7620 detected
[ 22.576414] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
[ 22.690534] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 119.261829] random: crng init done
[ 119.268656] random: 33 urandom warning(s) missed due to ratelimiting
[ 147.780456] urngd: v1.0.2 started.
[ 588.487150] e2fsck invoked oom-killer: gfp_mask=0x1100cca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0
[ 588.506318] CPU: 0 PID: 756 Comm: e2fsck Not tainted 5.15.137 #0
[ 588.518305] Stack : 00000000 00000004 00000000 00000000 00000000 00000000 00000000 00000000
[ 588.535005] 00000000 00000000 00000000 00000000 00000000 00000001 80e81c98 2d111d4a
[ 588.551709] 80e81d30 00000000 00000000 80e81b38 00000038 802ced04 00000000 ffffffea
[ 588.568418] 00000000 80e81b44 000000cd 806942d8 805de1e4 80e81c78 80ef3480 00000800
[ 588.585121] 00000000 00000840 01100cca 00000020 00000018 8032eca0 00000000 80850000
[ 588.601819] ...
[ 588.606703] Call Trace:
[ 588.606772] [<802ced04>] 0x802ced04
[ 588.618611] [<8032eca0>] 0x8032eca0
[ 588.625574] [<80006a80>] 0x80006a80
[ 588.632530] [<80006a88>] 0x80006a88
[ 588.639509] [<800fdd54>] 0x800fdd54
[ 588.646507] [<800fe5d4>] 0x800fe5d4
[ 588.653487] [<800fef84>] 0x800fef84
[ 588.660452] [<8014bb40>] 0x8014bb40
[ 588.667450] [<80135bbc>] 0x80135bbc
[ 588.674398] [<80138948>] 0x80138948
[ 588.681420] [<8001038c>] 0x8001038c
[ 588.688384] [<8011e850>] 0x8011e850
[ 588.695332] [<8007dd0c>] 0x8007dd0c
[ 588.702304] [<80015f30>] 0x80015f30
[ 588.709282]
[ 588.712241] Mem-Info:
[ 588.716764] active_anon:1210 inactive_anon:25015 isolated_anon:0
[ 588.716764] active_file:143 inactive_file:105 isolated_file:0
[ 588.716764] unevictable:0 dirty:0 writeback:0
[ 588.716764] slab_reclaimable:622 slab_unreclaimable:1232
[ 588.716764] mapped:260 shmem:5 pagetables:59 bounce:0
[ 588.716764] kernel_misc_reclaimable:0
[ 588.716764] free:1041 free_pcp:0 free_cma:0
[ 588.786086] Node 0 active_anon:4840kB inactive_anon:100060kB active_file:572kB inactive_file:420kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:1040kB dirty:0kB writeback:0kB shmem:20kB writeback_tmp:0kB kernel_stack:304kB pagetables:236kB all_unreclaimable? no
[ 588.834970] Normal free:4164kB min:5484kB low:5828kB high:6172kB reserved_highatomic:0KB active_anon:4840kB inactive_anon:100060kB active_file:572kB inactive_file:420kB unevictable:0kB writepending:0kB present:131072kB managed:122220kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 588.887501] lowmem_reserve[]: 0 0
[ 588.894109] Normal: 127*4kB (UM) 71*8kB (UM) 29*16kB (UM) 16*32kB (UM) 11*64kB (UM) 5*128kB (U) 3*256kB (UM) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 4164kB
[ 588.921427] 279 total pagecache pages
[ 588.928723] 0 pages in swap cache
[ 588.935315] Swap cache stats: add 0, delete 0, find 0/0
[ 588.945736] Free swap = 0kB
[ 588.951471] Total swap = 0kB
[ 588.957208] 32768 pages RAM
[ 588.962760] 0 pages HighMem/MovableOnly
[ 588.970398] 2213 pages reserved
[ 588.976655] Tasks state (memory values in pages):
[ 588.986018] [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name
[ 589.003199] [ 449] 81 449 368 111 20480 0 0 ubusd
[ 589.019515] [ 450] 0 450 264 86 16384 0 0 askfirst
[ 589.036351] [ 485] 0 485 302 102 16384 0 0 urngd
[ 589.052672] [ 714] 0 714 369 142 20480 0 0 S11fstab
[ 589.069513] [ 732] 0 732 551 164 16384 0 0 block
[ 589.085829] [ 756] 0 756 44764 26249 131072 0 0 e2fsck
[ 589.102323] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),global_oom,task_memcg=/,task=e2fsck,pid=756,uid=0
[ 589.122838] Out of memory: Killed process 756 (e2fsck) total-vm:179056kB, anon-rss:104296kB, file-rss:700kB, shmem-rss:0kB, UID:0 pgtables:128kB oom_score_adj:0
[ 594.169509] EXT4-fs (sda): recovery complete
[ 594.178079] EXT4-fs (sda): mounted filesystem with ordered data mode. Opts: . Quota mode: disabled.
[ 599.587571] zram0: detected capacity change from 0 to 262144
[ 599.714812] Adding 131068k swap on /dev/zram0. Priority:100 extents:1 across:131068k SSDsc
[ 633.663228] 8021q: adding VLAN 0 to HW filter on device eth0
[ 633.753422] br-lan: port 1(eth0) entered blocking state
[ 633.763950] br-lan: port 1(eth0) entered disabled state
[ 633.774809] device eth0 entered promiscuous mode
[ 633.923155] br-lan: port 1(eth0) entered blocking state
[ 633.933698] br-lan: port 1(eth0) entered forwarding state
[ 634.678859] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[ 637.343750] ksmbd: The ksmbd server is experimental, use at your own risk.
[ 645.311674] ksmbd: The ksmbd server is experimental, use at your own risk.
[ 666.423770] IPv6: ADDRCONF(NETDEV_CHANGE): phy0-ap0: link becomes ready