DraStic

1) Load whichever BIOS lets you load your current save in DeSmuME
That's where I'm stuck because the only savefile I can load in DeSmuME is a clean one that has been created with Official DS BIOS using DraStic. The contents of the file are wiped as soon as either emulator detects bad CRC.

The ...

Is there any other reason you're using the DS BIOSes?
No, just want to play the same game on play on PC, phone, or tablet, whatever's most convenient. I started playing this one on the tablet, but only found the savefile problem after about 20hrs of progress. It seems that using the official BIOS ...

Problem:
My savefile (Castlevania - Dawn of Sorrow (USA).dsv) gets corrupted and deleted after adding the official DS BIOS files to the system directory (nds_bios_arm9.bin and nds_bios_arm7.bin)

The error message is "Save data is corrupted Data has been deleted"

The result is identical to this ...