For each broken case, after a reboot of the phone they should be fixed and in the result of:
$ mc-tool dump
you should see:
- ofono/ofono/account0 with modem-objpath pointing to /ril_0
- ofono/ofono/account1 with modem-objpath pointing to /ril_1

Broken cases:
- Multiple accounts for each modem:
on the device, you can create extra accounts for each modem:
$ mc-tool add ofono/ofono "extra account for modem0" string:modem-objpath=/ril_0
$ mc-tool add ofono/ofono "extra account for modem1" string:modem-objpath=/ril_1

You can check you have two accounts for each modem by checking the output of:
$ mc-tool dump
at this point it should contain four ofono/ofono accounts.

- Accounts missing:
if the account for one given modem is missing, it should be recreated. You can manually remove one account or even both accounts like this:
$ mc-tool remove ofono/ofono/account0
$ mc-tool remove ofono/ofono/account1
at this point `mc-tool dump` should show no ofono/ofono accounts

- Accounts without the modem set correctly
if the account is not pointing to the correct modem (/ril_0 and /ril_1) this needs to be fixed too. To clear the modem property do the following:
$ mc-tool update ofono/ofono/account0 string:modem-objpath=
$ mc-tool update ofono/ofono/account1 string:modem-objpath=
at this point the modem names should not be visible anymore in `mc-tool dump`