<apex:page standardController="Case" >

<apex:form >
    <apex:pageBlock title="Update Asset Firmware" mode="edit">

        <apex:pageBlockButtons >
            <apex:commandButton value="Save" action="{!save}"/>
            <apex:commandButton value="Cancel" action="{!cancel}"/>
        </apex:pageBlockButtons>

        <apex:pageBlockSection columns="1">
                <apex:outputField value="{!case.AssetId}"/>
                <apex:inputField value="{!case.Asset.FW_version__c}"/>
                <apex:inputField value="{!case.Asset.FW_Confirmed_Date__c}"/>
        </apex:pageBlockSection>

    </apex:pageBlock>
</apex:form>