2 files changed, 77 insertions, 0 deletions
diff --git a/esp8266/modules/_boot.py b/esp8266/modules/_boot.py
new file mode 100644
index 0000000000..c950de6758
--- /dev/null
+++ b/esp8266/modules/_boot.py
@@ -0,0 +1,9 @@
+import uos
+from flashbdev import bdev
+
+try:
+    if bdev:
+        vfs = uos.VfsFat(bdev, "")
+except OSError:
+    import inisetup
+    vfs = inisetup.setup()
diff --git a/esp8266/modules/flashbdev.py b/esp8266/modules/flashbdev.py
new file mode 100644
index 0000000000..07ed966020
--- /dev/null
+++ b/esp8266/modules/flashbdev.py
@@ -0,0 +1,68 @@
+import esp
+
+class FlashBdev:
+
+    SEC_SIZE = 4096
+    START_SEC = 0x89000 // SEC_SIZE
+    NUM_BLK = 0x73
+
+    def __init__(self, blocks=NUM_BLK):
+        self.blocks = blocks
+
+    def readblocks(self, n, buf):
+        #print("readblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
+        esp.flash_read((n + self.START_SEC) * self.SEC_SIZE, buf)
+
+    def writeblocks(self, n, buf):
+        #print("writeblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
+        #assert len(buf) <= self.SEC_SIZE, len(buf)
+        esp.flash_erase(n + self.START_SEC)
+        esp.flash_write((n + self.START_SEC) * self.SEC_SIZE, buf)
+
+    def ioctl(self, op, arg):
+        #print("ioctl(%d, %r)" % (op, arg))
+        if op == 4:  # BP_IOCTL_SEC_COUNT
+            return self.blocks
+        if op == 5:  # BP_IOCTL_SEC_SIZE
+            return self.SEC_SIZE
+
+def set_bl_flash_size(real_size):
+    if real_size == 256*1024:
+        code = 1
+    elif real_size == 512*1024:
+        code = 0
+    elif real_size == 1024*1024:
+        code = 2
+    elif real_size == 2048*1024:
+        code = 3
+    elif real_size == 4096*1024:
+        code = 4
+    else:
+        code = 2
+    buf = bytearray(4096)
+    esp.flash_read(0, buf)
+    buf[3] = (buf[3] & 0xf) | (code << 4)
+    esp.flash_erase(0)
+    esp.flash_write(0, buf)
+
+# If bootloader size ID doesn't correspond to real Flash size,
+# fix bootloader value and reboot.
+size = esp.flash_id() >> 16
+# Check that it looks like realistic power of 2 for flash sizes
+# commonly used with esp8266
+if 22 >= size >= 18:
+    size = 1 << size
+    if size != esp.flash_size():
+        import machine
+        import time
+        print("Bootloader Flash size appear to have been set incorrectly, trying to fix")
+        set_bl_flash_size(size)
+        machine.reset()
+        while 1: time.sleep(1)
+
+size = esp.flash_size()
+if size < 1024*1024:
+    bdev = None
+else:
+    # 16K at the flash end is reserved for SDK params storage
+    bdev = FlashBdev((size - 16384) // FlashBdev.SEC_SIZE - FlashBdev.START_SEC)