Legal Question in Criminal Law in Maryland

It is NOT valid as a promissory note if it is not signed by the "maker" (i.e. the person who borrows the money and "promises" to pay it back must sign the note). The note does not need to be signed by the other party (the one getting the money).

But -- if there was a loan of some sort, an oral promise to repay can still be enforceable even if the note wasn't signed. How much was the note? what were the circumstances?