If you have stumbled into this blog, You're probably playing 'harvest moon DS' on Desmume, and don't have the bonus content from 'friends of mineral town'. I also had trouble finding anything on the internet, and spent a lot of time playing around with the emulator 'Desmume'  so I could get harvest moon to simulate the link between itself and FoMT. It was a very simple task in the end.

First of all, you need the resources.

DeSmuMe - http://www.coolrom.com/emulators/nds/84/DeSmuME.php
Harvest moon DS - http://www.coolrom.com/roms/nds/16927/Harvest_Moon_DS.php
or Harvest Moon DS Cute - http://www.coolrom.com/roms/nds/16530/Harvest_Moon_DS_Cute.php
And Friends of Mineral Town - http://www.coolrom.com/roms/gba/14404/Harvest_Moon_-_Friends_of_Mineral_Town.php
BIOS and Firmware- http://www.mediafire.com/download/l5k50s845r5ch0w/BIOS+and+Firmware.zip

It would be wise to organise these games neatly in their own folders like i have.

DS roms do NOT need to be extracted, they're readable as ZIP files when using DeSmuMe, However it may be a good idea to extract the .gba for FoMT.
One thing to mention, DeSmuMe is NOT a gameboy advance emulator, but it WILL identify them and it WILL crash when it tries to play them.

This is the Confusing part... Linking the Roms together.


Emulation > GBA slot

This screen will pop up

Browse for the gba game, which should be in your DS ROM folder and click Ok

To check that the DS can identify the gba game, you need DS BIOS and FIRMWARE (Resources)

download them and extract them to a subfolder in your DS pathway appropriately named Firmware.

Now you need to link the emulator to them.
Config > Emulation Settings.

This part is simple, Connect ARM9 to biosnds9 and ARM7 to biosnds7
and connect Firmware to.... Firmware
and tick the boxes like i have done.
Open the Harvest moon DS rom

Pretty neat huh?

Note that the gba game has been identified, That is good. Launch the DS game and keep these settings on temporarily.

Taada, It is tuesday and karen is in the valley, This means that the link worked! It is probably good to mention that it is difficult to tell whether the link has worked, sleep in your house, check what day it is and see if the character for that day has arrived in the valley, This may take some time.

Once the link is made you don't need to use the firmware anymore, it may reduce performance anyway, once you're sure the link is made, change the emulation settings
Goodluck!