diff --git a/legacy/firmware/.gitignore b/legacy/firmware/.gitignore
index 543117bf31..fce40a938d 100644
--- a/legacy/firmware/.gitignore
+++ b/legacy/firmware/.gitignore
@@ -1,6 +1,6 @@
 coin_info.[ch]
 nem_mosaics.[ch]
-ethereum_networks.h
+ethereum_networks.c
 ethereum_tokens.[ch]
 u2f_knownapps.h
 
diff --git a/legacy/firmware/Makefile b/legacy/firmware/Makefile
index 75a46b6ece..37264a4ac1 100644
--- a/legacy/firmware/Makefile
+++ b/legacy/firmware/Makefile
@@ -60,6 +60,7 @@ OBJS += crypto.o
 ifneq ($(BITCOIN_ONLY),1)
 OBJS += u2f.o
 OBJS += ethereum.o
+OBJS += ethereum_networks.o
 OBJS += ethereum_tokens.o
 OBJS += nem2.o
 OBJS += nem_mosaics.o
diff --git a/legacy/firmware/ethereum.c b/legacy/firmware/ethereum.c
index a6a01ccf14..5394603425 100644
--- a/legacy/firmware/ethereum.c
+++ b/legacy/firmware/ethereum.c
@@ -329,7 +329,7 @@ static void ethereumFormatAmount(const bignum256 *amnt, const TokenType *token,
     suffix = " Wei";
     decimals = 0;
   } else {
-    ASSIGN_ETHEREUM_SUFFIX(suffix, chain_id);
+    suffix = get_ethereum_suffix(chain_id);
   }
   bn_format(amnt, NULL, suffix, decimals, 0, false, ',', buf, buflen);
 }
diff --git a/legacy/firmware/ethereum_networks.h.mako b/legacy/firmware/ethereum_networks.c.mako
similarity index 66%
rename from legacy/firmware/ethereum_networks.h.mako
rename to legacy/firmware/ethereum_networks.c.mako
index 5049f883c6..c8f02b86e1 100644
--- a/legacy/firmware/ethereum_networks.h.mako
+++ b/legacy/firmware/ethereum_networks.c.mako
@@ -1,6 +1,4 @@
 <%
-BKSL = "\\"
-
 networks = list(supported_on("trezor1", eth))
 max_chain_id_length = 0
 max_slip44_length = 0
@@ -22,23 +20,21 @@ def align_suffix(n):
 	return "{:<{w}}".format(cstr, w=max_suffix_length + 4)
 
 %>\
-// This file is automatically generated from ethereum_networks.h.mako
+// This file is automatically generated from ethereum_networks.c.mako
 // DO NOT EDIT
 
-#ifndef __ETHEREUM_NETWORKS_H__
-#define __ETHEREUM_NETWORKS_H__
+#include "ethereum_networks.h"
 
-#define SLIP44_UNKNOWN UINT32_MAX
-
-#define ASSIGN_ETHEREUM_SUFFIX(suffix, chain_id) ${BKSL}
-  switch (chain_id) { ${BKSL}
+const char *get_ethereum_suffix(uint64_t chain_id) {
+  switch (chain_id) {
 % for n in networks:
-    case ${align_chain_id(n)}: suffix = ${align_suffix(n)} break;  /* ${n.name} */ ${BKSL}
+    case ${align_chain_id(n)}: return ${align_suffix(n)}  /* ${n.name} */
 % endfor
-    default: suffix = " UNKN"; break;  /* unknown chain */ ${BKSL}
+    default: return UNKNOWN_NETWORK_SHORTCUT;  /* unknown chain */
   }
+}
 
-static bool is_ethereum_slip44(uint32_t slip44) {
+bool is_ethereum_slip44(uint32_t slip44) {
   switch (slip44) {
 % for slip44 in sorted(set(n.slip44 for n in networks)):
     case ${slip44}:
@@ -49,7 +45,7 @@ static bool is_ethereum_slip44(uint32_t slip44) {
   }
 }
 
-static int32_t ethereum_slip44_by_chain_id(uint64_t chain_id) {
+int32_t ethereum_slip44_by_chain_id(uint64_t chain_id) {
   switch (chain_id) {
 % for n in networks:
     case ${align_chain_id(n)}: return ${align_slip44(n)};  /* ${n.name} */
@@ -57,5 +53,3 @@ static int32_t ethereum_slip44_by_chain_id(uint64_t chain_id) {
     default: return SLIP44_UNKNOWN;  /* unknown chain */
   }
 }
-
-#endif
diff --git a/legacy/firmware/ethereum_networks.h b/legacy/firmware/ethereum_networks.h
new file mode 100644
index 0000000000..00490f907b
--- /dev/null
+++ b/legacy/firmware/ethereum_networks.h
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (C) 2018 Pavol Rusnak <stick@satoshilabs.com>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ETHEREUM_NETWORKS_H__
+#define __ETHEREUM_NETWORKS_H__
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define SLIP44_UNKNOWN UINT32_MAX
+#define UNKNOWN_NETWORK_SHORTCUT " UNKN"
+
+const char *get_ethereum_suffix(uint64_t chain_id);
+bool is_ethereum_slip44(uint32_t slip44);
+int32_t ethereum_slip44_by_chain_id(uint64_t chain_id);
+
+#endif