YAYYYY!!!! Thanks judb! It works!
I think it was cleaning the phtsys on the new dms and adding the firmware files that did it. The original dms still does a weird thing now where it doesn't start the audio until you pause and unpause it, but that doesn't matter 'cause I'll be using the new one

For posterity, here is what I wrote before I tried the above:
That was the bootload.log of the old DMS. I have the SSA plugin, so renamed the plugins folder to no avail. Also tried corrupting the ramdisk.sig - the patchcomplete sound never happens, and it just plays track 1 of playlist one (I have to stop and start it to hear the audio, though).
Here is patchverify.log from the old DMS:
Starting Patch Process
PhatPatch v0.4 - original code by bushing, additional patches by sbingner
Verifying:
Patch 1 @ 0bb8: make drive signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 2 @ 0bec: make rc.sh signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 3 @ 0c20: make phatd signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 4 @ 0c54: make linux signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 5 @ 0354: make ramdisk invalid signature return 0 instead of 0xFFFFFFFF: [movlne r0, 0xFFFFFFFF -> movlne r0, #0]
Expected: 0000 13a0 Actual: 0000 13a0
Verified!
Patch 6 @ 0c80: make ramdisk signature check verify 0 instead of 1: [cmp r0, #1 -> cmp r0, #0]
Expected: 0000 e350 Actual: 0000 e350
Verified!
Patch 7 @ 0358: make ramdisk valid signature return 0 instead of 1: [moveq r0, #1 -> moveq r0, #0]
Expected: 0000 03a0 Actual: 0000 03a0
Verified!
PhatPatch v0.4 - original code by bushing, additional patches by sbingner
Verifying:
Patch 1 @ 0bb8: make drive signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 2 @ 0bec: make rc.sh signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 3 @ 0c20: make phatd signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 4 @ 0c54: make linux signature check always succeed: [bne verify_sig_failed -> bne PC+1]
Expected: 0000 1a00 Actual: 0000 1a00
Verified!
Patch 5 @ 0354: make ramdisk invalid signature return 0 instead of 0xFFFFFFFF: [movlne r0, 0xFFFFFFFF -> movlne r0, #0]
Expected: 0000 13a0 Actual: 0000 13a0
Verified!
Patch 6 @ 0c80: make ramdisk signature check verify 0 instead of 1: [cmp r0, #1 -> cmp r0, #0]
Expected: 0000 e350 Actual: 0000 e350
Verified!
Patch 7 @ 0358: make ramdisk valid signature return 0 instead of 1: [moveq r0, #1 -> moveq r0, #0]
Expected: 0000 03a0 Actual: 0000 03a0
Verified!