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.
SAMSUNG SSD 870 EVO 2.5" SATA III Solid State Drive 2TB 1TB 500GB 250GB lot
$230.72
SAMSUNG 2.5 inch SATA III SSD 870 EVO 2TB 1TB 500 GB 250GB Solid State Drive lot
$40.84
Netac Internal SSD 256GB Solid State Drive SATA III 6GB/s Wholesale Sale 530mb/s
$16.99
Netac 1TB 2TB 512GB Internal SSD 2.5'' SATA III 6Gb/s Solid State Drive lot
$16.99
Patriot P210 128GB 256GB 512GB 1TB 2TB 2.5" SATA 3 6GB/s Internal SSD PC/MAC Lot
$16.99
SanDisk SSD PLUS 240GB SATA III 2.5" 7mm SDSSDA-240G
$14.99
Western Digital 2.5" SSD WD BLUE 500 GB 3D NAND WDS500G2B0A SATA Laptop
$24.95
Patriot P300 128G 256GB 512GB 1TB 2TB M.2 2280 PCIe Gen3x4 NVMe Internal SSD Lot
$14.99
SOLIDE STATE DRIVE 128GB/256GB SATA M.2 SSD WITH PRE-ACTIVATED WINDOWS 10/11 PRO
$11.99
Fanxiang SSD 1TB 2.5'' SATA SSD 6Gb/s 550MB/s Internal Solid State Drive PC Lot
$45.99