Omnia kernel 4.14.113 seems to be unstable
I and as a reference few other encountered problems with Omnia kernel on HBK. The problem seems to be in i2c bus driver. It might be something different but considering that i2c hub initialization is happening during that time and when router starts it reports problem right in that moment for pca953x.
Following is log with failure
[ 13.385520] i2c i2c-0: Added multiplexed i2c bus 1
[ 13.390509] i2c i2c-0: Added multiplexed i2c bus 2
[ 13.396027] i2c i2c-0: Added multiplexed i2c bus 3
[ 13.401381] i2c i2c-0: Added multiplexed i2c bus 4
[ 13.406560] i2c i2c-0: Added multiplexed i2c bus 5
[ 13.411776] i2c i2c-0: Added multiplexed i2c bus 6
[ 13.416898] i2c i2c-0: Added multiplexed i2c bus 7
[ 13.419056] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[ 13.429811] pgd = ed6bc000
[ 13.432522] [00000004] *pgd=2d618831, *pte=00000000, *ppte=00000000
[ 13.438808] Internal error: Oops: 80000007 [#1] SMP ARM
[ 13.444043] Modules linked in: i2c_mux_pca954x(+) i2c_mux ledtrig_oneshot ledtrig_heartbeat ledtrig_gpio xt_set ip_set_list_set ip_set_hash_netportnet ip_set_hash_netport ip_set_hash_netnet ip_set_hash_netiface ip_set_hash_net ip_set_hash_mac ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_hash_ipport ip_set_hash_ipmark ip_set_hash_ip ip_set_bitmap_port ip_set_bitmap_ipmac ip_set_bitmap_ip ip_set nfnetlink nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables ip6t_REJECT x_tables nf_reject_ipv6 ifb sit ip6_tunnel tunnel6 tunnel4 ip_tunnel ledtrig_transient
[ 13.494942] CPU: 1 PID: 1308 Comm: grep Tainted: G W 4.14.113 #0
[ 13.502091] Hardware name: Marvell Armada 380/385 (Device Tree)
[ 13.508023] task: ee9f8540 task.stack: edb2e000
[ 13.512563] PC is at 0x4
[ 13.515102] LR is at show_interrupts+0x23c/0x374
[ 13.519728] pc : [<00000004>] lr : [<c0172bc8>] psr: 20000093
[ 13.526007] sp : edb2fe68 ip : 00000002 fp : c0b03c70
[ 13.531241] r10: c0b61230 r9 : edc74500 r8 : eeaf1e00
[ 13.536476] r7 : 00000004 r6 : c0b03d74 r5 : 0000004b r4 : ee16c700
[ 13.543017] r3 : eeb6053c r2 : 00000004 r1 : ee16c700 r0 : edc74514
[ 13.549559] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none
[ 13.556796] Control: 10c5387d Table: 2d6bc04a DAC: 00000051
[ 13.562554] Process grep (pid: 1308, stack limit = 0xedb2e210)
[ 13.568399] Stack: (0xedb2fe68 to 0xedb30000)
[ 13.572765] fe60: 00000041 edc74568 a0000013 eeaf1e00 ee402198 ee16c700
[ 13.580962] fe80: edb2feb8 00000000 00000585 0000004a 00000000 ed5ad480 edb2ff80 c0236414
[ 13.589159] fea0: 00000000 ee16c730 00018000 00dda000 0000004a 00000000 0000004b 00000000
[ 13.597356] fec0: 00000000 c023609c 00000000 00000000 eeb36100 00dda000 00018000 00000003
[ 13.605552] fee0: 00000000 c0268cd0 c0268c70 00000000 00000000 00000000 00dda000 c02125a0
[ 13.613749] ff00: 5cc0680b 068e7780 5cc0680b 068e7780 5cc0680b 068e7780 f0000046 00000000
[ 13.621945] ff20: be881b38 be881b38 00045098 be881dc8 000000c5 c02174c4 000007ff 00008124
[ 13.630142] ff40: 00000001 00000400 00000000 ed5ad480 00000000 00000000 00000000 c0212750
[ 13.638338] ff60: 00000004 00000000 ed5ad480 ed5ad480 00000000 00000000 00dda000 c0212c24
[ 13.646534] ff80: 00000000 00000000 5cc0680b 00000000 00000000 00018000 00000003 c01079a4
[ 13.654730] ffa0: edb2e000 c01077a0 00000000 00000000 00000003 00dda000 00018000 00000000
[ 13.662927] ffc0: 00000000 00000000 00018000 00000003 00dda000 00000000 00dd9010 00000000
[ 13.671124] ffe0: be881a78 be881a64 b6f0d340 b6f0c800 60000010 00000003 00000000 00000000
[ 13.679327] [<c0172bc8>] (show_interrupts) from [<c0236414>] (seq_read+0x378/0x528)
[ 13.687005] [<c0236414>] (seq_read) from [<c0268cd0>] (proc_reg_read+0x60/0x90)
[ 13.694335] [<c0268cd0>] (proc_reg_read) from [<c02125a0>] (__vfs_read+0x1c/0x118)
[ 13.701923] [<c02125a0>] (__vfs_read) from [<c0212750>] (vfs_read+0xb4/0x13c)
[ 13.709076] [<c0212750>] (vfs_read) from [<c0212c24>] (SyS_read+0x3c/0x7c)
[ 13.715971] [<c0212c24>] (SyS_read) from [<c01077a0>] (ret_fast_syscall+0x0/0x54)
[ 13.723471] Code: bad PC value
[ 13.726531] ---[ end trace 215502d5bb9398fa ]---
[ 13.731680] Kernel panic - not syncing: Fatal exception
[ 13.736918] CPU0: stopping
[ 13.739634] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G D W 4.14.113 #0
[ 13.746958] Hardware name: Marvell Armada 380/385 (Device Tree)
[ 13.752900] [<c010edac>] (unwind_backtrace) from [<c010aa7c>] (show_stack+0x10/0x14)
[ 13.760664] [<c010aa7c>] (show_stack) from [<c07a26e8>] (dump_stack+0x88/0x9c)
[ 13.767904] [<c07a26e8>] (dump_stack) from [<c010dbec>] (handle_IPI+0xe4/0x190)
[ 13.775231] [<c010dbec>] (handle_IPI) from [<c0101494>] (gic_handle_irq+0x8c/0x90)
[ 13.782818] [<c0101494>] (gic_handle_irq) from [<c010b70c>] (__irq_svc+0x6c/0x90)
[ 13.790316] Exception stack(0xc0b01f50 to 0xc0b01f98)
[ 13.795378] 1f40: 00000001 00000000 00000000 c0114540
[ 13.803575] 1f60: ffffe000 c0b03cc0 c0b03c70 00000000 00000000 414fc091 00000000 00000000
[ 13.811770] 1f80: c0b01f98 c0b01fa0 c0108168 c010816c 60000013 ffffffff
[ 13.818401] [<c010b70c>] (__irq_svc) from [<c010816c>] (arch_cpu_idle+0x34/0x38)
[ 13.825815] [<c010816c>] (arch_cpu_idle) from [<c015fd14>] (do_idle+0xdc/0x19c)
[ 13.833142] [<c015fd14>] (do_idle) from [<c0160030>] (cpu_startup_entry+0x18/0x1c)
[ 13.840730] [<c0160030>] (cpu_startup_entry) from [<c0a00d5c>] (start_kernel+0x494/0x4a0)
[ 13.849257] Rebooting in 1 seconds..
And here when system starts
[ 13.026794] i2c i2c-0: Added multiplexed i2c bus 1
[ 13.031982] i2c i2c-0: Added multiplexed i2c bus 2
[ 13.037294] i2c i2c-0: Added multiplexed i2c bus 3
[ 13.042420] i2c i2c-0: Added multiplexed i2c bus 4
[ 13.047375] i2c i2c-0: Added multiplexed i2c bus 5
[ 13.052538] i2c i2c-0: Added multiplexed i2c bus 6
[ 13.057567] i2c i2c-0: Added multiplexed i2c bus 7
[ 13.062828] pca953x 8-0071: 8-0071 supply vcc not found, using dummy regulator
[ 13.075743] i2c i2c-0: Added multiplexed i2c bus 8
[ 13.080550] pca954x 0-0070: registered 8 multiplexed busses for I2C mux pca9547