fix: RPC fallback transports and native balance display for weth wrappers

src/core/config/registry/hft/README.md

@@ -34,7 +34,8 @@ use HFT contracts on EVM and `pallet-hft` on Substrate.
       type: "wrapped-hft",
       underlying: "0x...",  // canonical ERC20
       weth: true,           // only if the contract's isWeth() is true:
-                            // sends spend native via msg.value, balances read native
+                            // sends spend native via msg.value; the app shows the
+                            // native balance and symbol (e.g. tBNB) in the form
     },
     {
       chainId: Base.chainId,

src/core/config/wagmi.ts

@@ -1,7 +1,7 @@
 import type { NetworkConfig } from "@hyperbridge-fe/shared"
 import { EVM_NETWORKS, VIEM_CHAIN_MAP } from "@hyperbridge-fe/shared/config"
 import { getDefaultConfig } from "connectkit"
-import type { HttpTransport } from "viem"
+import { fallback, type Transport } from "viem"
 import { createConfig, http } from "wagmi"
 import { coinbaseWallet, injected, walletConnect } from "wagmi/connectors"
 import { APP_NAME, APP_URL, NETWORK_ENV, WALLET_CONNECT_ID } from "@/config/constants"
@@ -52,10 +52,16 @@ function createWagmiConfig(): any {
   return createConfig(getDefaultConfig(config as any))
 }
 
+// Fall back through every configured RPC so one flaky endpoint doesn't
+// zero out balances or block sends for the whole chain.
 const networkToTransport = (
   network: NetworkConfig,
-): [number, HttpTransport] => {
-  return [Number(network.chainId), http(network.rpcUrls[0])]
+): [number, Transport] => {
+  const transports = network.rpcUrls.map((url) => http(url))
+  return [
+    Number(network.chainId),
+    transports.length > 1 ? fallback(transports) : transports[0],
+  ]
 }
 
 export type WagmiChainId = number

src/core/lib/balance-helper.ts

@@ -227,7 +227,9 @@ export const BalanceHelper = {
         chainId,
       })
 
-      return BalanceImpl.create(balance.value, decimals, symbol)
+      // Users spend the native token, so show its symbol (e.g. tBNB), not the
+      // wrapper's registry symbol.
+      return BalanceImpl.create(balance.value, balance.decimals, balance.symbol)
     }
 
     const underlying =

src/core/lib/fee-token-preparation.ts

@@ -15,6 +15,7 @@ import { TokenFaucetABI } from "@/abis/TokenFaucet"
 import { gatewayConfig } from "@/config/services/gateway-config"
 import { WagmiConfig } from "@/config/wagmi"
 import { rootLogger } from "@/lib/logger"
+import { evmFeeOverrides } from "@/lib/utils/gas"
 
 const logger = rootLogger.withTag("FeeTokenPrep")
 
@@ -134,13 +135,16 @@ export async function requestFeeTokenDrip(params: {
 
   await switchChain(WagmiConfig, { chainId: params.source.chainId })
 
+  const feeOverrides = await evmFeeOverrides(params.source.chainId)
+
   const hash = await writeContract(WagmiConfig, {
     abi: TokenFaucetABI,
     address: faucet,
     functionName: "drip",
     args: [params.feeTokenAddress],
     chainId: params.source.chainId,
     account: params.owner,
+    ...feeOverrides,
   })
 
   await waitForTransactionReceipt(WagmiConfig, {

src/core/lib/transactions/bridge-hft.ts

@@ -20,6 +20,7 @@ import {
   isHftToken,
 } from "@/lib/hft/hyper-fungible-token"
 import { rootLogger } from "@/lib/logger"
+import { evmFeeOverrides } from "@/lib/utils/gas"
 import type { EVMToken } from "@/types"
 import type { TxCreationEvents } from "@/types/tx"
 import { WagmiConfig, type WagmiChainId } from "@/config/wagmi"
@@ -90,6 +91,8 @@ export class HftBridgeTx implements BridgeTxExecutor {
       throw new Error("Wallet not connected")
     }
 
+    const feeOverrides = await evmFeeOverrides(source.chainId)
+
     const gen = hft.bridge({
       token: token.address,
       from: account.address,
@@ -113,6 +116,7 @@ export class HftBridgeTx implements BridgeTxExecutor {
           to: step.tx.to,
           data: step.tx.data,
           chainId: source.chainId as WagmiChainId,
+          ...feeOverrides,
         })
         await waitForTransactionReceipt(WagmiConfig, {
           hash,
@@ -129,6 +133,7 @@ export class HftBridgeTx implements BridgeTxExecutor {
           data: step.tx.data,
           value: step.tx.value,
           chainId: source.chainId as WagmiChainId,
+          ...feeOverrides,
         })
 
         yield {

src/core/lib/utils/__tests__/gas.test.ts

@@ -0,0 +1,40 @@
+import { parseGwei } from "viem"
+import { describe, expect, it } from "vitest"
+import { clampToMinPriorityFee } from "../gas"
+
+describe("clampToMinPriorityFee", () => {
+  const floor = parseGwei("25")
+
+  it("raises an undershooting tip to the floor and keeps base-fee headroom", () => {
+    const result = clampToMinPriorityFee(
+      {
+        maxPriorityFeePerGas: parseGwei("1.5"),
+        maxFeePerGas: parseGwei("2"), // 0.5 gwei of base-fee headroom
+      },
+      floor,
+    )
+
+    expect(result.maxPriorityFeePerGas).toBe(floor)
+    expect(result.maxFeePerGas).toBe(floor + parseGwei("0.5"))
+  })
+
+  it("leaves estimates above the floor untouched", () => {
+    const fees = {
+      maxPriorityFeePerGas: parseGwei("30"),
+      maxFeePerGas: parseGwei("80"),
+    }
+
+    expect(clampToMinPriorityFee(fees, floor)).toEqual(fees)
+  })
+
+  it("never returns maxFeePerGas below the tip", () => {
+    const result = clampToMinPriorityFee(
+      { maxPriorityFeePerGas: parseGwei("1"), maxFeePerGas: parseGwei("1") },
+      floor,
+    )
+
+    expect(result.maxFeePerGas).toBeGreaterThanOrEqual(
+      result.maxPriorityFeePerGas,
+    )
+  })
+})

src/core/lib/utils/gas.ts

@@ -0,0 +1,52 @@
+import { estimateFeesPerGas } from "@wagmi/core"
+import { parseGwei } from "viem"
+import { WagmiConfig } from "@/config/wagmi"
+import { rootLogger } from "@/lib/logger"
+
+const logger = rootLogger.withTag("Gas")
+
+/**
+ * Bor (Polygon) chains reject transactions with a priority fee below 25 gwei,
+ * and wallet estimators regularly undershoot it (MetaMask suggests 1.5 gwei),
+ * failing broadcasts with "transaction gas price below minimum".
+ */
+const MIN_PRIORITY_FEE: Record<number, bigint> = {
+  137: parseGwei("25"),
+  80002: parseGwei("25"),
+}
+
+export type FeeOverrides = {
+  maxFeePerGas?: bigint
+  maxPriorityFeePerGas?: bigint
+}
+
+/** Raises the priority fee to the floor, keeping the base-fee headroom intact. */
+export function clampToMinPriorityFee(
+  fees: { maxFeePerGas: bigint; maxPriorityFeePerGas: bigint },
+  minPriorityFee: bigint,
+): Required<FeeOverrides> {
+  const tip =
+    fees.maxPriorityFeePerGas >= minPriorityFee
+      ? fees.maxPriorityFeePerGas
+      : minPriorityFee
+  const basePortion = fees.maxFeePerGas - fees.maxPriorityFeePerGas
+
+  return { maxPriorityFeePerGas: tip, maxFeePerGas: basePortion + tip }
+}
+
+/**
+ * Explicit fee fields for chains whose minimum priority fee wallets undershoot.
+ * Returns {} elsewhere so the wallet keeps estimating on its own.
+ */
+export async function evmFeeOverrides(chainId: number): Promise<FeeOverrides> {
+  const floor = MIN_PRIORITY_FEE[chainId]
+  if (!floor) return {}
+
+  try {
+    const fees = await estimateFeesPerGas(WagmiConfig, { chainId })
+    return clampToMinPriorityFee(fees, floor)
+  } catch (err) {
+    logger.warn(`Fee estimation failed for Chain(${chainId})`, err)
+    return {}
+  }
+}

src/shared/config/registry/evm-networks.ts

@@ -225,8 +225,9 @@ export const BscTestnet: EVMChainConfig = {
   chainId: 97,
   stateMachineId: "EVM-97",
   rpcUrls: [
-    "https://bsc-testnet-rpc.publicnode.com",
+    "https://data-seed-prebsc-1-s1.bnbchain.org:8545",
     `https://bnb-testnet.g.alchemy.com/v2/${ALCHEMY_API_KEY}`,
+    "https://bsc-testnet-rpc.publicnode.com",
     "https://bsc-geth-testnet-rpc.blockops.network",
   ],
   networkType: "testnet",