I have a D505 and I had the same problem with 3.9 and 4.0 until I installed 4.0 to the hard drive then the screen resolution problem went away. Note that I like 4.0 a lot but its a little buggy.
Knoppix 3.7 works very fine on my notebook, but the 3.9 not.
Every time I boot it, the resolution is always 640 x 480 and I can't change it.
Any suggestion ?
I have a D505 and I had the same problem with 3.9 and 4.0 until I installed 4.0 to the hard drive then the screen resolution problem went away. Note that I like 4.0 a lot but its a little buggy.
I've been having trouble with v 3.9 on my d505 also. I get an x-server error during boot up.
I have tried some of the cheat codes and also seen some posts that suggest that the x-server error may be due to a flaw on the CD.
I'll keep digging for an answer.

Kingston 32GB 64GB 128GB 256GB USB 3.0 Flash Drive Thumb Memory Stick Pen lot
$285.90
TF/SD Card Adapter Camera Reader Android Type-c For iPhone17 Pro Max Plusm lot
$573.98
SK HYNIX 32GB 2RX4 PC4 2666V ECC SERVER RAM
$199.00
Windows 11 Pro Install/Recovery/Repair USB Flash Drive
$35.00
USB 3.0 Flash Drive 32GB 64GB 128GB Memory Stick Thumb Stick Lot Pack
$826.09
USB 3.0 Micro SD SDHC TF Card Reader Memory Adapter for PC Laptop Camera lot
$3.75
Samsung 32GB DDR4-2666V-2Rx4-RB2-12 RAM M393A4K40CB2-CTD6Q
$169.00
A-Tech 8GB DDR3 1600 PC3-12800 Laptop SODIMM 204-Pin Memory RAM PC3L DDR3L 1x 8G
$21.68
5 in 1 Memory Card Reader USB 3.0 OTG Adapter SD Card Reader For iPhone/iPad LOT
$9.99
SMART(Micron)SafeStor 32GB(1X32GB) 1RX4 NN4-3200AA(DDR4) HPE Server Memory
$159.98