diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 2a61a5d6f0..2edb872cc6 100644
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -37,7 +37,11 @@
 # include <mtd/mtd-user.h>
 #endif
 
+#ifndef __packed
+#define __packed __attribute__((packed))
+#endif
 #include <mtd/ubi-user.h>
+#undef __packed
 
 #include "fw_env_private.h"
 #include "fw_env.h"
@@ -484,7 +488,8 @@ int fw_printenv(int argc, char *argv[], int value_only, struct env_opts *opts)
 
 		val = fw_getenv(name);
 		if (!val) {
-			fprintf(stderr, "## Error: \"%s\" not defined\n", name);
+			if (!value_only)
+				fprintf(stderr, "## Error: \"%s\" not defined\n", name);
 			rc = -1;
 			continue;
 		}
@@ -1725,6 +1730,105 @@ static int check_device_config(int dev)
 	return rc;
 }
 
+#define CRC_SZ 4
+
+// By default use 0x10000 but then can be changed after detection
+static size_t env_len = 0x10000;
+
+// Detect U-Boot environment area offset
+static int uboot_detect_env(void *buf, size_t size, size_t erasesize) {
+	size_t possible_lens[] = {0x10000, 0x40000, 0x20000};
+
+	// Jump over memory by step
+	int scan_step = erasesize;
+
+	for (int baddr = 0; baddr < size; baddr += scan_step) {
+		uint32_t expected_crc = *(int *)(buf + baddr);
+
+		for (int i = 0; i < sizeof(possible_lens) / sizeof(possible_lens[0]);
+				i++) {
+			if (possible_lens[i] + baddr > size)
+				continue;
+
+			uint32_t crc = crc32(0, buf + baddr + CRC_SZ, possible_lens[i] - CRC_SZ);
+
+#if 0
+			printf("Detecting at %#x with len %#x CRC is %#x ~ %#x\n", baddr,
+					possible_lens[i], crc, expected_crc);
+#endif
+			if (crc == expected_crc) {
+				env_len = possible_lens[i];
+				return baddr;
+			}
+		}
+	}
+
+	return -1;
+}
+
+static char *open_mtdblock(int i, int *fd, uint32_t size, int flags) {
+	char filename[PATH_MAX];
+
+	snprintf(filename, sizeof filename, "/dev/mtdblock%d", i);
+	*fd = open(filename, O_RDONLY);
+	if (*fd == -1) {
+		return NULL;
+	}
+
+	char *addr =
+		(char *)mmap(NULL, size, PROT_READ, MAP_PRIVATE | flags, *fd, 0);
+	if ((void *)addr == MAP_FAILED) {
+		close(*fd);
+		return NULL;
+	}
+
+	return addr;
+}
+
+static char dev[80];
+static int detect_env(void) {
+	FILE *fp;
+	char name[80];
+	int i, es, ee;
+	struct mtd_info_user mtd;
+	int res = 0;
+
+	if ((fp = fopen("/proc/mtd", "r"))) {
+		bool running = true;
+		while (fgets(dev, sizeof dev, fp) && running) {
+			name[0] = 0;
+			if (sscanf(dev, "mtd%d: %x %x \"%64[^\"]\"", &i, &es, &ee, name)) {
+				snprintf(dev, sizeof dev, "/dev/mtd%d", i);
+				int devfd = open(dev, O_RDWR);
+				if (devfd < 0)
+					continue;
+
+				if (ioctl(devfd, MEMGETINFO, &mtd) >= 0) {
+					int blockfd;
+					char *addr = open_mtdblock(
+								i, &blockfd, mtd.size, MAP_POPULATE /* causes read-ahead on the file */);
+					if (!addr)
+						return res;
+					int off = uboot_detect_env(addr, mtd.size, mtd.erasesize);
+					close(blockfd);
+					if (off != -1) {
+						DEVNAME(0) = dev;
+						DEVOFFSET(0) = off;
+						ENVSIZE(0) = env_len;
+						DEVESIZE(0) = mtd.erasesize;
+						ENVSECTORS(0) = env_len / mtd.erasesize;
+						res = 1;
+						break;
+					}
+				}
+				close(devfd);
+			}
+		}
+		fclose(fp);
+	}
+	return res;
+}
+
 static int parse_config(struct env_opts *opts)
 {
 	int rc;
@@ -1735,9 +1839,26 @@ static int parse_config(struct env_opts *opts)
 #if defined(CONFIG_FILE)
 	/* Fills in DEVNAME(), ENVSIZE(), DEVESIZE(). Or don't. */
 	if (get_config(opts->config_file)) {
-		fprintf(stderr, "Cannot parse config file '%s': %m\n",
-			opts->config_file);
-		return -1;
+		if (!detect_env()) {
+			fprintf(stderr, "Cannot parse config file '%s': %m\n",
+				opts->config_file);
+			return -1;
+		}
+		FILE* f = fopen(opts->config_file, "wb");
+		if (f == NULL) {
+			fprintf(stderr, "Cannot open config file '%s': %m\n",
+				opts->config_file);
+			return -1;
+		}
+		if (fprintf(f, "%s\t%#llx\t%#lx\t%#lx\t%#lx\n",
+			    DEVNAME(0),
+			    DEVOFFSET(0),
+			    ENVSIZE(0), DEVESIZE(0), ENVSECTORS(0)) < 0) {
+			fprintf(stderr, "Cannot write config file '%s': %m\n",
+				opts->config_file);
+			return -1;
+		}
+		fclose(f);
 	}
 #else
 	DEVNAME(0) = DEVICE1_NAME;