diff --git a/Makefile b/Makefile
index 6d993e7..c3bf071 100644
--- a/Makefile
+++ b/Makefile
@@ -386,7 +386,8 @@
 
 CHIP_OBJS = memory_bus.o jedec.o stm50.o w39.o w29ee011.o \
 	sst28sf040.o 82802ab.o \
-	sst49lfxxxc.o sst_fwhub.o edi.o flashchips.o spi.o spi25.o spi25_statusreg.o \
+	sst49lfxxxc.o sst_fwhub.o edi.o flashchips.o \
+	spi.o spi25.o spi25_prepare.o spi25_statusreg.o \
 	spi95.o opaque.o sfdp.o en29lv640b.o at45db.o \
 	writeprotect.o writeprotect_ranges.o
 
diff --git a/include/chipdrivers.h b/include/chipdrivers.h
index 1ac5e53..272b65c 100644
--- a/include/chipdrivers.h
+++ b/include/chipdrivers.h
@@ -28,6 +28,7 @@
 int spi_chip_read(struct flashctx *flash, uint8_t *buf, unsigned int start, int unsigned len);
 
 /* spi25.c */
+int spi_simple_write_cmd(struct flashctx *flash, uint8_t op, unsigned int poll_delay);
 int probe_spi_rdid(struct flashctx *flash);
 int probe_spi_rdid4(struct flashctx *flash);
 int probe_spi_rems(struct flashctx *flash);
@@ -57,9 +58,9 @@
 int spi_chip_write_1(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len);
 int spi_nbyte_read(struct flashctx *flash, uint8_t *dst, unsigned int addr, unsigned int len);
 int spi_write_chunked(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len, unsigned int chunksize);
-int spi_enter_4ba(struct flashctx *flash);
-int spi_exit_4ba(struct flashctx *flash);
 int spi_set_extended_address(struct flashctx *, uint8_t addr_high);
+
+/* spi25_prepare.c */
 int spi_prepare_4ba(struct flashctx *, enum preparation_steps);
 
 
diff --git a/meson.build b/meson.build
index efe10cd..408b87a 100644
--- a/meson.build
+++ b/meson.build
@@ -69,6 +69,7 @@
   'programmer_table.c',
   'sfdp.c',
   'spi25.c',
+  'spi25_prepare.c',
   'spi25_statusreg.c',
   'spi95.c',
   'spi.c',
diff --git a/spi25.c b/spi25.c
index 82fe4a8..30ccc30 100644
--- a/spi25.c
+++ b/spi25.c
@@ -308,7 +308,7 @@
  * @param poll_delay  interval in us for polling WIP, don't poll if zero
  * @return 0 on success, non-zero otherwise
  */
-static int spi_simple_write_cmd(struct flashctx *const flash, const uint8_t op, const unsigned int poll_delay)
+int spi_simple_write_cmd(struct flashctx *const flash, const uint8_t op, const unsigned int poll_delay)
 {
 	struct spi_command cmds[] = {
 	{
@@ -797,64 +797,3 @@
 		msg_cerr("%s failed to disable AAI mode.\n", __func__);
 	return SPI_GENERIC_ERROR;
 }
-
-static int spi_enter_exit_4ba(struct flashctx *const flash, const bool enter)
-{
-	const unsigned char cmd = enter ? JEDEC_ENTER_4_BYTE_ADDR_MODE : JEDEC_EXIT_4_BYTE_ADDR_MODE;
-	int ret = 1;
-
-	if (flash->chip->feature_bits & FEATURE_4BA_ENTER)
-		ret = spi_send_command(flash, sizeof(cmd), 0, &cmd, NULL);
-	else if (flash->chip->feature_bits & FEATURE_4BA_ENTER_WREN)
-		ret = spi_simple_write_cmd(flash, cmd, 0);
-	else if (flash->chip->feature_bits & FEATURE_4BA_ENTER_EAR7)
-		ret = spi_set_extended_address(flash, enter ? 0x80 : 0x00);
-
-	if (!ret)
-		flash->in_4ba_mode = enter;
-	return ret;
-}
-
-int spi_enter_4ba(struct flashctx *const flash)
-{
-	return spi_enter_exit_4ba(flash, true);
-}
-
-int spi_exit_4ba(struct flashctx *flash)
-{
-	return spi_enter_exit_4ba(flash, false);
-}
-
-int spi_prepare_4ba(struct flashctx *const flash, const enum preparation_steps prep)
-{
-	if (prep != PREPARE_FULL)
-		return 0;
-
-	flash->address_high_byte = -1;
-	flash->in_4ba_mode = false;
-
-	/* Be careful about 4BA chips and broken masters */
-	if (flash->chip->total_size > 16 * 1024 && spi_master_no_4ba_modes(flash)) {
-		/* If we can't use native instructions, bail out */
-		if ((flash->chip->feature_bits & FEATURE_4BA_NATIVE) != FEATURE_4BA_NATIVE
-		    || !spi_master_4ba(flash)) {
-			msg_cerr("Programmer doesn't support this chip. Aborting.\n");
-			return 1;
-		}
-	}
-
-	/* Enable/disable 4-byte addressing mode if flash chip supports it */
-	if (flash->chip->feature_bits & (FEATURE_4BA_ENTER | FEATURE_4BA_ENTER_WREN | FEATURE_4BA_ENTER_EAR7)) {
-		int ret;
-		if (spi_master_4ba(flash))
-			ret = spi_enter_4ba(flash);
-		else
-			ret = spi_exit_4ba(flash);
-		if (ret) {
-			msg_cerr("Failed to set correct 4BA mode! Aborting.\n");
-			return 1;
-		}
-	}
-
-	return 0;
-}
diff --git a/spi25_prepare.c b/spi25_prepare.c
new file mode 100644
index 0000000..7fb1a10
--- /dev/null
+++ b/spi25_prepare.c
@@ -0,0 +1,81 @@
+/*
+ * This file is part of the flashprog project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+
+#include <stdbool.h>
+#include "flash.h"
+#include "chipdrivers.h"
+#include "programmer.h"
+#include "spi_command.h"
+#include "spi.h"
+
+static int spi_enter_exit_4ba(struct flashctx *const flash, const bool enter)
+{
+	const unsigned char cmd = enter ? JEDEC_ENTER_4_BYTE_ADDR_MODE : JEDEC_EXIT_4_BYTE_ADDR_MODE;
+	int ret = 1;
+
+	if (flash->chip->feature_bits & FEATURE_4BA_ENTER)
+		ret = spi_send_command(flash, sizeof(cmd), 0, &cmd, NULL);
+	else if (flash->chip->feature_bits & FEATURE_4BA_ENTER_WREN)
+		ret = spi_simple_write_cmd(flash, cmd, 0);
+	else if (flash->chip->feature_bits & FEATURE_4BA_ENTER_EAR7)
+		ret = spi_set_extended_address(flash, enter ? 0x80 : 0x00);
+
+	if (!ret)
+		flash->in_4ba_mode = enter;
+	return ret;
+}
+
+static int spi_enter_4ba(struct flashctx *const flash)
+{
+	return spi_enter_exit_4ba(flash, true);
+}
+
+static int spi_exit_4ba(struct flashctx *flash)
+{
+	return spi_enter_exit_4ba(flash, false);
+}
+
+int spi_prepare_4ba(struct flashctx *const flash, const enum preparation_steps prep)
+{
+	if (prep != PREPARE_FULL)
+		return 0;
+
+	flash->address_high_byte = -1;
+	flash->in_4ba_mode = false;
+
+	/* Be careful about 4BA chips and broken masters */
+	if (flash->chip->total_size > 16 * 1024 && spi_master_no_4ba_modes(flash)) {
+		/* If we can't use native instructions, bail out */
+		if ((flash->chip->feature_bits & FEATURE_4BA_NATIVE) != FEATURE_4BA_NATIVE
+		    || !spi_master_4ba(flash)) {
+			msg_cerr("Programmer doesn't support this chip. Aborting.\n");
+			return 1;
+		}
+	}
+
+	/* Enable/disable 4-byte addressing mode if flash chip supports it */
+	if (flash->chip->feature_bits & (FEATURE_4BA_ENTER | FEATURE_4BA_ENTER_WREN | FEATURE_4BA_ENTER_EAR7)) {
+		int ret;
+		if (spi_master_4ba(flash))
+			ret = spi_enter_4ba(flash);
+		else
+			ret = spi_exit_4ba(flash);
+		if (ret) {
+			msg_cerr("Failed to set correct 4BA mode! Aborting.\n");
+			return 1;
+		}
+	}
+
+	return 0;
+}