Most of this text is from ackmed.
I have no GD-R discs to swap in, so I tried loading a system 2.0
which worked just great for some reason.
You want to download and burn the following 2 images
boot with the bbapassport one first. You will want to use that disc configure an ip address/netmask/gateway for the dreamcast. This data will be saved to the dreamcast's flash area and is what httpd-ack uses for its ip.
Then boot the httpd-ack disc. On screen you should see the url to use to access it. Should be http://<ip you did for bbapassport>/.
Swap in system 2.0
Fire up your browser on your desktop and put in that url. It should bring up a webpage listing the disc info for httpd-ack disc along with track01.raw track02.bin.
Open, load in GDR. No need to spin down, no need to tape lid switch.
Perhaps due to the system 2.0 special magic.
If you are using httpd-ack to dump, by default its going to abort on any read error. This can be overridden by changing the dumping options.
If you hover over the track urls you can see them. I would suggest adjusting the following options
abort1 -> abort0, continue on read error
sector_read16 -> sector_read1, read 1 sector at a time