Although I'm sure Adobe won't support this, here's what I use to reset the password to "password":
MySQL:
update EDCPRINCIPALADMINENTITY admin, EDCPRINCIPALUSERENTITY user set
admin.salt='WLbfSEMZqVG9fsC+aw5Lkw==',
admin.password='oG2JunzcbpI3aChXix4Af23lL0w=',
admin.accountlocked=0,
admin.unsuccessfulauthattempts=0,
admin.isactive=1
where admin.principalid=user.principalid and
user.uidstring='administrator';
SQL Server:
update EDCPRINCIPALADMINENTITY set
salt='WLbfSEMZqVG9fsC+aw5Lkw==',
password='oG2JunzcbpI3aChXix4Af23lL0w=',
accountlocked=0,
unsuccessfulauthattempts=0,
isactive=1
from EDCPRINCIPALADMINENTITY, EDCPRINCIPALUSERENTITY
where EDCPRINCIPALADMINENTITY.principalid=EDCPRINCIPALUSERENTITY.principalid and
EDCPRINCIPALUSERENTITY.uidstring='administrator';
Keep in mind that by using a known salt, you can reduce your security.