message: op-chain-ops: safety with params
  Check for `nil` when getting the chain params.
  Also log info about the chain params
diff: package ether
  import (
  + "fmt"
  "math/big"
  "github.com/ethereum-optimism/optimism/op-bindings/predeploys"
  @@ -40,6 +41,10 @@ func MigrateLegacyETH(db ethdb.Database, addresses []common.Address, allowances
  storageSlotsToMigrate := make(map[common.Hash]int)
  // Chain params to use for integrity checking.
  params := ParamsByChainID[chainID]
  + if params == nil {
  + return common.Hash{}, fmt.Errorf("no chain params for %d", chainID)
  + }
  + log.Info("Chain params", "chain-id", chainID, "supply-delta", params.ExpectedSupplyDelta)
  // Iterate over each address list, and read the addresses they
  // contain into memory. Also calculate the storage slots for each
  