The DSi firmware files don't work with any NDS Phat, Lite or even iQue DS only emulator. Since the DSi has DSi enhanced features at the hardware, bios & firmware level. The files are as follows.
These 4 are used for DSi.
bios7i.bin
Size: 64.00KB (65536B)
MD5: c8b9fe70f1ef5cab8e55540cd1c13dc8
bios9i.bin
Size: 64.00KB (65536B)
MD5: 3fbb3f39bd9a96e5d743f138bd4b9907
BIOSDSI7.ROM
Size: 64.00KB (65536B)
MD5: 559dae4ea78eb9d67702c56c1d791e81
BIOSDSI9.ROM
Size: 64.00KB (65536B)
MD5: 87b665fce118f76251271c3732532777
As of yet those 4 can't be used by DraStic.
There's also a 128kb firmware.bin for DS Phat, Lite & iQue DS emulation in The DSi & The 3DS. The 3DS one has better compatibility than The DSi one. Dump it from your own 3DS, preferably New 3DS, or you can search it online. I don't know the checksum of it nor if it'd work with any emulator other than MelonDS with direct game boot turned since those specific 128kb firmware.bin files lack the boot code.
These 2 are used for NDS.
biosnds7.rom
Size: 16.00KB (16384B)
MD5: df692a80a5b1bc90728bc3dfc76cd948
biosnds9.rom
Size: 4.00KB (4096B)
MD5: a392174eb3e572fed6447e956bde4b25
For DSi ROM emulation you're welcome to check out
viewtopic.php?f=4&t=2210 or use NO$GBA emulator for that & DSi enhanced features.
Also for any emulator that doesn't require enceypted roms or isos use decrypted & trimmed roms. They run faster & smoother. DraStic has a DS rom trimmer that can be used by launching DraStic, click change options, then advanced & turn on auto trim rom. There's software online to decrypt your roms & even anonymous No-Intro rom dumpers make an effort to maintain decrypted rom dump archives across the internet.
https://www.reddit.com/r/emulation/comm ... ntro_roms/