You wouldn't believe this simple trick that freed 10 kB of RAM!

user/apars_csi.c

@@ -760,7 +760,7 @@ do_csi_xterm_screen_cmd(CSI_Data *opts)
 
 // data tables for the DECREPTPARM command response
 struct DECREPTPARM_parity { int parity; const char * msg; };
-static const struct DECREPTPARM_parity DECREPTPARM_parity_arr[] = {
+static const struct DECREPTPARM_parity DECREPTPARM_parity_arr[] ESP_CONST_DATA = {
 	{PARITY_NONE, "1"},
 	{PARITY_ODD, "4"},
 	{PARITY_EVEN, "5"},
@@ -768,7 +768,7 @@ static const struct DECREPTPARM_parity DECREPTPARM_parity_arr[] = {
 };
 
 struct DECREPTPARM_baud { int baud; const char * msg; };
-static const struct DECREPTPARM_baud DECREPTPARM_baud_arr[] = {
+static const struct DECREPTPARM_baud DECREPTPARM_baud_arr[] ESP_CONST_DATA = {
 	{BIT_RATE_300, "48"},
 	{BIT_RATE_600, "56"},
 	{BIT_RATE_1200, "64"},

user/character_sets.h

@@ -12,7 +12,7 @@
 #define CODEPAGE_A_BEGIN 35
 #define CODEPAGE_A_END 35
 
-static const u16 codepage_A[] =
+static const u16 codepage_A[] ESP_CONST_DATA =
 	{//	Unicode    ASCII   SYM
 		// %%BEGIN:A%%
 		0x20a4, // 35   #   £
@@ -26,7 +26,7 @@ static const u16 codepage_A[] =
  * translates VT100 ACS escape codes to Unicode values.
  * Based on rxvt-unicode screen.C table.
  */
-static const u16 codepage_0[] =
+static const u16 codepage_0[] ESP_CONST_DATA =
 	{//	Unicode    ASCII   SYM
 		// %%BEGIN:0%%
 		0x2666, // 96	`	♦
@@ -66,7 +66,7 @@ static const u16 codepage_0[] =
 #define CODEPAGE_1_BEGIN 33
 #define CODEPAGE_1_END 126
 
-static const u16 codepage_1[] =
+static const u16 codepage_1[] ESP_CONST_DATA =
 	{//	Unicode    ASCII   SYM  DOS
 		// %%BEGIN:1%%
 		0x263A,	// 33	!	☺	(1)  - low ASCII symbols from DOS, moved to +32

user/routes.c

@@ -22,7 +22,7 @@ static int wifiPassFn(HttpdConnData *connData, int no, char *user, int userLen,
 /**
  * Application routes
  */
-HttpdBuiltInUrl routes[] = {
+const HttpdBuiltInUrl routes[] ESP_CONST_DATA = {
 	// redirect func for the captive portal
 	ROUTE_CGI_ARG("*", cgiRedirectApClientToHostname, "esp-terminal.ap"),
 

user/routes.h

@@ -4,7 +4,7 @@
 #include <esp8266.h>
 #include <httpd.h>
 
-extern HttpdBuiltInUrl routes[];
+extern const HttpdBuiltInUrl routes[];
 
 /** Broadcast screen state to sockets */
 void screen_notifyChange();