CHanged the error text and added text for odd number of digits for

calldata

src/app/ui/universal-dapp-ui.js

@@ -133,7 +133,11 @@ UniversalDAppUI.prototype.renderInstanceFromABI = function (contractABI, address
         <label class="pt-2 border-top d-flex justify-content-start flex-grow-1">
           Low level interactions
         </label>
-        <a href="https://solidity.readthedocs.io/en/v0.6.2/contracts.html#receive-ether-function" title="check out docs for using 'receive'/'fallback'" target="_blank">
+        <a
+          href="https://solidity.readthedocs.io/en/v0.6.2/contracts.html#receive-ether-function"
+          title="check out docs for using 'receive'/'fallback'"
+          target="_blank"
+        >
           <i aria-hidden="true" class="fas fa-info text-info my-2 mr-2"></i>
         </a>
       </div>
@@ -176,13 +180,13 @@ UniversalDAppUI.prototype.renderInstanceFromABI = function (contractABI, address
     let calldata = calldataInput.value
     if (calldata) {
       if (calldata.length < 2 || calldata.length < 4 && helper.is0XPrefixed(calldata)) {
-        return setLLIError('the calldata should be a valid hexadecimal value with size of at least one byte.')
+        return setLLIError('The calldata should be a valid hexadecimal value with size of at least one byte.')
       } else {
         if (helper.is0XPrefixed(calldata)) {
           calldata = calldata.substr(2, calldata.length)
         }
         if (!helper.isHexadecimal(calldata)) {
-          return setLLIError('the calldata should be a valid hexadecimal value with size of at least one byte.')
+          return setLLIError('The calldata should be a valid hexadecimal value.')
         }
       }
       if (!fallback) {

test-browser/tests/specialFunctions.js

@@ -34,7 +34,19 @@ module.exports = {
         browser.sendLowLevelTx(address, '0', '0xa')
         .pause(1000)
         .waitForElementVisible(`#instance${address} label[id="deployAndRunLLTxError"]`)
-        .assert.containsText(`#instance${address} label[id="deployAndRunLLTxError"]`, `the calldata should be a valid hexadecimal value with size of at least one byte.`)
+        .assert.containsText(`#instance${address} label[id="deployAndRunLLTxError"]`, `The calldata should be a valid hexadecimal value with size of at least one byte.`)
+        .perform(done)
+      })
+    })
+  },
+  'Use special functions receive/fallback - both are declared, failing sending data with odd number of digits': function (browser) {
+    // don't need to redeploy it, same contract
+    browser.perform((done) => {
+      browser.getAddressAtPosition(0, (address) => {
+        browser.sendLowLevelTx(address, '0', '0x1aa')
+        .pause(1000)
+        .waitForElementVisible(`#instance${address} label[id="deployAndRunLLTxError"]`)
+        .assert.containsText(`#instance${address} label[id="deployAndRunLLTxError"]`, `The calldata should be a valid hexadecimal value.`)
         .perform(done)
       })
     })