Here is the binwalk of the OEM current firmware. My "defective" unit is not running this same version. It's running a very old one, actually. This switch has failed on me about 2 years ago and I just recently found the time to see if it's still salvageable.
cesarvog@ubuntu:~/Unifi$ binwalk -e US.bcm5334x_5.43.34+12682.210318.0402.bin
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
0 0x0 Ubiquiti firmware header, header size: 264 bytes, ~CRC32: 0xA43D534C, version: "US.bcm5334x.v5.43.34+12682.210318.0402"
268 0x10C Ubiquiti partition header, header size: 56 bytes, name: "PARTu-boot", base address: 0x1C000000, data size: 443926 bytes
281552 0x44BD0 CRC32 polynomial table, little endian
325488 0x4F770 gzip compressed data, maximum compression, from Unix, last modified: 2013-04-09 21:31:53
433824 0x69EA0 CRC32 polynomial table, little endian
444258 0x6C762 Ubiquiti partition header, header size: 56 bytes, name: "PARTkernel0", base address: 0x1C0E0000, data size: 15117696 bytes
444314 0x6C79A uImage header, header size: 64 bytes, header CRC: 0x933AD13D, created: 2021-03-18 04:10:43, image size: 15117632 bytes, Data Address: 0x18000, Entry Point: 0x18000, data CRC: 0x36C962F9, OS: Linux, CPU: ARM, image type: OS Kernel Image, compression type: none, image name: "Ubiquiti 5.43.34.12682"
1559231 0x17CABF Certificate in DER format (x509 v3), header length: 4, sequence length: 1284
1559351 0x17CB37 Certificate in DER format (x509 v3), header length: 4, sequence length: 1288
2433319 0x252127 Certificate in DER format (x509 v3), header length: 4, sequence length: 1292
2433323 0x25212B Certificate in DER format (x509 v3), header length: 4, sequence length: 1316
2433327 0x25212F Certificate in DER format (x509 v3), header length: 4, sequence length: 1320
2979916 0x2D784C Linux kernel version 3.6.5
3451044 0x34A8A4 Unix path: /sys/bcm/mem
3451086 0x34A8CE Unix path: /sys/bcm/mem
3451134 0x34A8FE Unix path: /sys/bcm/mem
3516802 0x35A982 xz compressed data
3574391 0x368A77 Neighborly text, "NeighborSolicitsgrams"
3574408 0x368A88 Neighborly text, "NeighborAdvertisements"
3576758 0x3693B6 Neighborly text, "neighbor %.2x%.2x.%pM lostename link %s to %s"
3956394 0x3C5EAA LZMA compressed data, properties: 0x6D, dictionary size: 1048576 bytes, uncompressed size: -1 bytes
15441370 0xEB9DDA CRC32 polynomial table, little endian
15486258 0xEC4D32 Intel x86 or x64 microcode, sig 0x18012fff, pf_mask 0x00, 2000-18-01, size 2048
15496605 0xEC759D LZMA compressed data, properties: 0xC0, dictionary size: 0 bytes, uncompressed size: 32 bytes
15562018 0xED7522 Signed Ubiquiti end header, RSA 2048 bit, header size: 264 bytes