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.
Cisco UCS LSI MegaRAID 9271CV-8I SAS2308 PCIe SAS Internal RAID Controller
$28.00
ACASIS 2.5/3.5 inch 2 Bay SATA USB 3.0 Hard Drive Disk HDD SSD Enclosure 4 RAID
$58.99
Intel PCIe SSD AIC RAID Controller Card G97168-252
$44.55
LSI 9305-16i SATA SAS 12Gbs RAID Controller PCIe 3.0 x8 IT-Mode 4* 8643 SATA
$229.99
Inspur LSI 9300-8i Raid Card 12Gbps HBA HDD Controller High Profile IT MODE
$15.98
LSI MegaRAID 9361-8i 12Gb PCIe 8-Port SAS/SATA RAID 1Gb w/BBU/CacheVault/License
$39.95
LSI MegaRaid 9361-8i 12Gbps SAS / SATA Raid Controller PCIe x8 3.0 Tested
$29.00
ORICO Multi Bay RAID Hard Drive Enclosure USB 3.0/ Type-C For 2.5/3.5'' HDD SSDs
$87.99
4 Bay RAID External Hard Drive Enclosure for 2.5/3.5" SATA HDD/SSD
$79.99
G TECHNOLOGY G RAID 0G04228 2-Bay Thunderbolt 2 RAID Array W/Power Supply
$99.99