Dreamshell suddenly stopped working

[DreamBol]

Hi, I have 1999 Sega Dreamcast VA1 console from PAL region. I have installed ATA cable to it's GD-ROM and could boot Dreamshell from externall HDD using Dreamshell boot CD. But then I wanted to install dual bios mod using piggyback method, I have followed steps from this tutorial:
https://web.archive.org/web/202304281738...free-bios/

I was able to switch between original bios and uprogrammed chip using switch, but I couldn't boot from HDD. Dreamshell boot loader sometimes detected HDD correctly and opened boot selection menu other times it shows FatFs 5 error. I have tried to boot using SD card which doesn't work. I have tried to remove ATA cable after that Dreamshell boot loader started to stuck at searching for G1 ATA devices... . Then I have removed additional bios chip leaving only original bios, I have broken a 12 pin of original BIOS IC but console loaded BIOS without problems.

Out of curiosity I have soldered ATA cable directly to motherboard but it doesn't changed anything. Then I have screwed everything together and since then console gives no AV signal output.

What could caused such issues? I won't be able to check the console for two weeks but I am searching for any suggestions.

[Elgor4uk]

1. If the original BIOS chip has the 12th pin removed, then the screen will be black when booting, because the BIOS will not boot. There are exceptions when the original BIOS can boot with the 12th pin removed:
If an additional BIOS chip is installed on top + a switch is installed between the custom and original BIOS. And even if the original BIOS has the 12th pin removed, it can still be booted by disabling the custom one. However, it does not work with all GDroms. Tested and loaded the BIOS on NTSC-J VA0, when the original BIOS has the 12th pin removed.

2. You can restore the 12th pin of the original BIOS. You need to cut off the stone case a little, near the removed 12th pin. A sharp knife + a very small file + cleaning with alcohol helped me. Solder a very, very thin wire the size of a hair to this small cleaned area.

3. In vain you deleted the custom BIOS after an unsuccessful attempt. You should have asked for help on this forum and looked for a solution. I suppose that your unsuccessful piggyback method bios mod was in the incomplete soldering of certain pins. I suppose that the FatFs 5 error is due to incorrect soldering of pin 23.

[DreamBol]

I need to add that I have used 1k resistors instead of 10k and here are photos of my piggyback bios mod.