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.
HP ProLiant MicroServer Gen8 G8 G2020T 8GB RAM 4x 1TB HDD 4x 3.5" 712318-421
$249.99
1U BareMetal pfsense opnsense Router Firewall DNS Server 6x 10GB Ethernet Ports
$149.00
1U Supermicro Server 10 Bay 2x Intel Xeon 3.3Ghz 8C 128GB RAM 480GB SSD 2x 10GBE
$273.00
$198.00
HP ProLiant MicroServer Gen8 Onboard SSD Xeon E3-1220L 16gb RAM (4) 4TB HDs
$250.00
HP Proliant MicroServer (Model: HSTNS-5151) NO HARD DRIVES-Power Tested,
$99.99
SuperMicro Server 505-2 Intel Atom 2.4GHz 8GB RAM SYS-5018A-FTN4 1U Rackmount
$202.49
HP PROLIANT MICROSERVER GEN8 PENTIUM G2020T 2.50GHZ 4GB RAM NO HDD/OS T8-E6
$108.00
Supermicro 1U Server X9SRI-F Xeon E5-2640 v2 2.5Ghz 16-Cores / 64GB / No HDD
$149.99
2U 12 Bay SAS3 SuperMicro Server 6028U-TR4T+ W/ X10DRU-i+ Barebone 12 Caddy RAIL
$299.00