From f91723fdd58ddb95d5087f0ebd719c6ae94ef99c Mon Sep 17 00:00:00 2001
From: Alex Miller <asmiller1989@gmail.com>
Date: Tue, 15 Jun 2021 14:00:22 -0500
Subject: [PATCH] Fixes issue introduced in v0.7.22 In some cases we want hex
 buffers to represent `0` with a 0-length buffer, and in others we want it
 represented as a 1-byte buffer `00`

---
 package-lock.json |  2 +-
 package.json      |  2 +-
 src/ethereum.js   | 12 ++++++++----
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 79fe6e2a..2126483a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "gridplus-sdk",
-  "version": "0.7.22",
+  "version": "0.7.23",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 7d943370..2ba4d39c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "gridplus-sdk",
-  "version": "0.7.22",
+  "version": "0.7.23",
   "description": "SDK to interact with GridPlus Lattice1 device",
   "scripts": {
     "commit": "git-cz",
diff --git a/src/ethereum.js b/src/ethereum.js
index 9dad053b..67d73655 100644
--- a/src/ethereum.js
+++ b/src/ethereum.js
@@ -428,10 +428,13 @@ function isBase10NumStr(x) {
 
 // Ensure a param is represented by a buffer
 // TODO: Remove circular dependency in util.js so that we can put this function there
-function ensureHexBuffer(x) {
+function ensureHexBuffer(x, zeroIsNull=true) {
   try {
-    // For null values, return a 0-sized buffer
-    if (x === null) return Buffer.alloc(0);
+    // For null values, return a 0-sized buffer. For most situations we assume
+    // 0 should be represented with a zero-length buffer (e.g. for RLP-building
+    // txs), but it can also be treated as a 1-byte buffer (`00`) if needed
+    if (x === null || (x === 0 && zeroIsNull === true)) 
+      return Buffer.alloc(0);
     const isNumber = typeof x === 'number' || isBase10NumStr(x);
     // Otherwise try to get this converted to a hex string
     if (isNumber) {
@@ -646,7 +649,8 @@ function parseEIP712Item(data, type, isEthers=false) {
       data = `0x${data.toString('hex')}`
     }
   } else if (type === 'uint8' || type === 'uint16' || type === 'uint32' || type === 'uint64') {
-    data = parseInt(ensureHexBuffer(data).toString('hex'), 16)
+    // In this case we want the hex buffer to represent `0` as a 1-byte buffer (`00`)
+    data = parseInt(ensureHexBuffer(data, false).toString('hex'), 16)
   } else if (type === 'uint256') {
     let b = ensureHexBuffer(data);
     // Edge case to handle 0-value bignums