While snooping around the stock init script, I spotted a variable, home, in the mountdata function standing out from the crowd. After doing some quick tests, the preliminary results are summarised as follows,
Prerequisite: The persistent overlay (.img, .aes or .inf) being on the same partition as the KNOPPIX file.
Functionality: Loading a specific persistent overlay at the boot time.
Usage: knoppix home=/mnt-system/foobar/dummy
*The dirname and basename cannot contain any whitespace characters.
*The basename needs to be unique if there are more than one overlay files in the same folder because the suffix cannot be part of the argument.
Supermicro 4U 36 Bay Storage Server 2.4Ghz 8-C 128GB 1x1280W Rails TrueNAS ZFS
$712.98
DELL PowerEdge R730XD 24x 2.5" Server Dual 750W Dual Heatsink - BareBones TESTED
$299.99
H261-Z61 2U 24SFF AMD Server 8x EPYC 7551 256-Cores 256GB RAM 8x25G NIC 2x2200W
$2612.18
Dell Poweredge R640 Server | 2x Xeon Gold 6132 | 128GB | H730P | 8x HDD Trays
$1849.00
Dell PowerEdge R620 Server 2x E5-2660 v1 2.2GHz 16 Cores 256GB RAM 2x 300GB HDD
$89.99
Dell PowerEdge R730XD 28 Core Server 2X Xeon E5-2680 V4 H730 128GB RAM No HDD
$389.99
Dell PowerEdge R720 Server - 2x8c CPU,256Gb RAM, 128Gb SSD/3x900Gb SAS, Proxmox
$340.00
SuperMicro Server 505-2 Intel Atom 2.4GHz 8GB RAM SYS-5018A-FTN4 1U Rackmount
$202.49
DELL PowerEdge R730 Server 2x E5-2680v4 2.4GHz =28 Cores 32GB H730 4xRJ45
$284.00
HP ProLiant DL380 Gen9 8SFF Server - E5-2698 v3 - 32Cores - 128GB Ram - 1TB HDD
$299.00