hos: add bc based mem mode support

README.md

@@ -66,7 +66,7 @@ Custom Graphical Nintendo Switch bootloader, firmware patcher, tools, and many m
 
 ## Bootloader configuration
 
-The bootloader can be configured via 'bootloader/hekate_ipl.ini' (if it is present on the SD card). Each ini section represents a boot entry, except for the special section 'config' that controls the global configuration.
+The bootloader can be configured via `Nyx` -> `Options` or 'bootloader/hekate_ipl.ini'. The special section 'config' controls the actual global configuration. Any other ini section represents a boot entry and can only be edited manually via the ini.
 
 
 There are four possible type of entries. "**[ ]**": Boot entry, "**{ }**": Caption, "**#**": Comment, "*newline*": .ini cosmetic newline.
@@ -75,7 +75,9 @@ There are four possible type of entries. "**[ ]**": Boot entry, "**{ }**": Capti
 **You can find a template [Here](./res/hekate_ipl_template.ini)**
 
 
-### hekate Global Configuration keys/values (when entry is *[config]*):
+### hekate Configuration keys/values (section *[config]*)
+
+Use `Options` in Nyx to edit the following configuration:
 
 | Config option      | Description                                                    |
 | ------------------ | -------------------------------------------------------------- |
@@ -91,7 +93,9 @@ There are four possible type of entries. "**[ ]**": Boot entry, "**{ }**": Capti
 | bootprotect=0      | 0: Disable, 1: Protect bootloader folder from being corrupted by disallowing reading or editing in HOS. |
 
 
-### Boot entry key/value combinations:
+### Boot entry key/value combinations
+
+A boot entry needs to be manually added/edited with the user's chosen key/value combos.
 
 | Config option          | Description                                                |
 | ---------------------- | ---------------------------------------------------------- |
@@ -141,7 +145,9 @@ You can define `kip1` to load an extra kip or many via the wildcard (`/*`) usage
 That's in case the kips are incompatible between them. If compatible, you can override `pkg3`/`fss0` kips with no issues (useful for testing with intermediate kip changes). In such cases, the `kip1` line must be **after** `pkg3`/`fss0` line.
 
 
-### Boot entry key/value combinations for Exosphère:
+### Boot entry key/value combinations for Exosphère
+
+The following can be paired together with a HOS boot entry:
 
 | Config option          | Description                                                |
 | ---------------------- | ---------------------------------------------------------- |
@@ -150,6 +156,7 @@ That's in case the kips are incompatible between them. If compatible, you can ov
 | cal0blank=1            | Overrides Exosphère config `blank_prodinfo_{sys/emu}mmc`. If that key doesn't exist, `exosphere.ini` will be used. |
 | cal0writesys=1         | Overrides Exosphère config `allow_writing_to_cal_sysmmc`. If that key doesn't exist, `exosphere.ini` will be used. |
 | usb3force=1            | Overrides system settings mitm config `usb30_force_enabled`. If that key doesn't exist, `system_settings.ini` will be used. |
+| memmode=1              | Enables boot config memory mode for retail units. By default, max ram is limited to 4GB. Enabling this will automatically choose size. |
 
 
 **Note**: `cal0blank`, `cal0writesys`, `usb3force`, as stated override the `exosphere.ini` or `system_settings.ini`. 0: Disable, 1: Enable, Key Missing: Use original value.
@@ -158,7 +165,7 @@ That's in case the kips are incompatible between them. If compatible, you can ov
 **Note2**: `blank_prodinfo_{sys/emu}mmc`, `allow_writing_to_cal_sysmmc` and `usb30_force_enabled` in `exosphere.ini` and `system_settings.ini` respectively, are the only atmosphere config keys that can affect hekate booting configuration externally, **if** the equivalent keys in hekate config are missing.
 
 
-### Payload storage:
+## Payload storage
 
 hekate has a boot storage in the binary that helps it configure it outside of BPMP environment:
 
@@ -174,7 +181,9 @@ hekate has a boot storage in the binary that helps it configure it outside of BP
 | '0xA0' emummc_path[120] | When `Boot to emuMMC` is set, it will override the current emuMMC (boot entry or emummc.ini). Must be NULL terminated. |
 
 
-### Nyx Configuration keys/values (nyx.ini):
+## Nyx Configuration keys/values (nyx.ini)
+
+Use `Nyx Settings` in Nyx to edit the following configuration:
 
 | Config option      | Description                                                |
 | ------------------ | ---------------------------------------------------------- |

bootloader/hos/hos.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018 naehrwert
- * Copyright (c) 2018-2025 CTCaer
+ * Copyright (c) 2018-2026 CTCaer
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -63,9 +63,10 @@ enum {
 
 typedef struct _exo_ctxt_t
 {
-	u32  hos_revision;
+	u32   hos_revision;
-	bool no_user_exceptions;
+	bool  no_user_exceptions;
-	bool user_pmu;
+	bool  user_pmu;
+	bool *force_mem_mode;
 	bool *usb3_force;
 	bool *cal0_blank;
 	bool *cal0_allow_writes_sys;

bootloader/hos/hos_config.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018 naehrwert
- * Copyright (c) 2018-2025 CTCaer
+ * Copyright (c) 2018-2026 CTCaer
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -223,6 +223,20 @@ static int _config_exo_user_pmu_access(launch_ctxt_t *ctxt, const char *value)
 	return 0;
 }
 
+static int _config_exo_force_mem_mode(launch_ctxt_t *ctxt, const char *value)
+{
+	// Override key found.
+	ctxt->exo_ctx.force_mem_mode = zalloc(sizeof(bool));
+
+	if (*value == '1')
+	{
+		DPRINTF("Enabled Auto Memory Mode\n");
+		*ctxt->exo_ctx.force_mem_mode = true;
+	}
+
+	return 0;
+}
+
 static int _config_exo_usb3_force(launch_ctxt_t *ctxt, const char *value)
 {
 	// Override key found.
@@ -312,6 +326,7 @@ static const cfg_handler_t _config_handlers[] = {
 	{ "emummcforce",      _config_emummc_forced },
 	{ "nouserexceptions", _config_dis_exo_user_exceptions },
 	{ "userpmu",          _config_exo_user_pmu_access },
+	{ "memmode",          _config_exo_force_mem_mode },
 	{ "usb3force",        _config_exo_usb3_force },
 	{ "cal0blank",        _config_exo_cal0_blanking },
 	{ "cal0writesys",     _config_exo_cal0_writes_enable },

bootloader/hos/secmon_exo.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2025 CTCaer
+ * Copyright (c) 2018-2026 CTCaer
  * Copyright (c) 2019 Atmosphère-NX
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -136,6 +136,7 @@ typedef struct _atm_fatal_error_ctx
 #define  EXO_FLAG_CAL0_BLANKING   BIT(5)
 #define  EXO_FLAG_CAL0_WRITES_SYS BIT(6)
 #define  EXO_FLAG_ENABLE_USB3     BIT(7)
+#define  EXO_FLAG_BC_MEM_MODE     BIT(8)
 
 #define EXO_FW_VER(mj, mn) (((mj) << 24) | ((mn) << 16))
 
@@ -145,6 +146,7 @@ void config_exosphere(launch_ctxt_t *ctxt, u32 warmboot_base)
 	u32 exo_flags = 0;
 	bool usb3_force = false;
 	bool user_debug = false;
+	bool bc_mem_mode = false;
 	bool cal0_blanking = false;
 	bool cal0_allow_writes_sys = false;
 
@@ -224,6 +226,8 @@ void config_exosphere(launch_ctxt_t *ctxt, u32 warmboot_base)
 						exo_cfg->uart_invert = atoi(kv->val);
 					else if (!strcmp("log_baud_rate", kv->key))
 						exo_cfg->uart_baudrate = atoi(kv->val);
+					else if (!strcmp("enable_mem_mode", kv->key))
+						bc_mem_mode = atoi(kv->val);
 					else if (emu_cfg.enabled && !h_cfg.emummc_force_disable)
 					{
 						if (!strcmp("blank_prodinfo_emummc", kv->key))
@@ -283,6 +287,11 @@ void config_exosphere(launch_ctxt_t *ctxt, u32 warmboot_base)
 	if (ctxt->exo_ctx.user_pmu)
 		exo_flags |= EXO_FLAG_USER_PMU;
 
+	// Enable Boot Config Memory Mode. Check if system_settings ini value is overridden. If not, check if enabled in ini.
+	if ((ctxt->exo_ctx.force_mem_mode && *ctxt->exo_ctx.force_mem_mode)
+			|| (!ctxt->exo_ctx.force_mem_mode && bc_mem_mode))
+		exo_flags |= EXO_FLAG_BC_MEM_MODE;
+
 	// Enable USB 3.0. Check if system_settings ini value is overridden. If not, check if enabled in ini.
 	if ((ctxt->exo_ctx.usb3_force && *ctxt->exo_ctx.usb3_force)
 			|| (!ctxt->exo_ctx.usb3_force && usb3_force))