From 3fe9eec27652c6a3cd0810761daa7c156f47b3b4 Mon Sep 17 00:00:00 2001
From: Stephan Hadinger <stephan.hadinger@gmail.com>
Date: Sun, 28 Aug 2022 09:39:24 +0200
Subject: [PATCH] Berry bootloader flasher

---
 tasmota/berry/modules/bootloader.be | 99 +++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 tasmota/berry/modules/bootloader.be

diff --git a/tasmota/berry/modules/bootloader.be b/tasmota/berry/modules/bootloader.be
new file mode 100644
index 000000000..5124a5b60
--- /dev/null
+++ b/tasmota/berry/modules/bootloader.be
@@ -0,0 +1,99 @@
+#
+# Flash bootloader from URL
+#
+
+class bootloader
+  static var _addr = [0x1000, 0x0000]         # possible addresses for bootloader
+  static var _sign = bytes('E9')              # signature of the bootloader
+  static var _addr_high = 0x8000              # address of next partition after bootloader
+
+  # get the bootloader address, 0x1000 for Xtensa based, 0x0000 for RISC-V based (but might have some exception)
+  # we prefer to probed what's already in place rather than manage a hardcoded list of architectures
+  # (there is a low risk of collision if the address is 0x0000 and offset 0x1000 is actually E9)
+  def get_bootloader_address()
+    import flash
+    # let's see where we find 0xE9, trying first 0x1000 then 0x0000
+    for addr : self._addr
+      if flash.read(addr, size(self._sign)) == self._sign
+        return addr
+      end
+    end
+    return nil
+  end
+
+  #
+  # download from URL and store to `bootloader.bin`
+  #
+  def download(url)
+    # address to flash the bootloader
+    var addr = self.get_bootloader_address()
+    if addr == nil    raise "internal_error", "can't find address for bootloader" end
+    
+    var cl = webclient()
+    cl.begin(url)
+    var r = cl.GET()
+    if r != 200    raise "network_error", "GET returned "+str(r) end
+    var bl_size = cl.get_size()
+    if bl_size <= 8291   raise "internal_error", "wrong bootloader size "+str(bl_size) end
+    if bl_size > (0x8000 - addr)  raise "internal_error", "bootloader is too large "+str(bl_size / 1024)+"kB" end
+
+    cl.write_file("bootloader.bin")
+    cl.close()
+  end
+
+  def flash(url)
+    if url != nil
+      self.download(url)
+    end
+    # address to flash the bootloader
+    var addr = self.get_bootloader_address()
+    if addr == nil    raise "internal_error", "can't find address for bootloader" end
+
+    var bl = open("bootloader.bin", "r")
+    if bl.readbytes(size(self._sign)) != self._sign
+      raise "value_error", "the file does not contain a bootloader signature"
+    end
+    bl.seek(0)    # reset to start of file
+
+    var bl_size = bl.size()
+    if bl_size <= 8291   raise "internal_error", "wrong bootloader size "+str(bl_size) end
+    if bl_size > (0x8000 - addr)  raise "internal_error", "bootloader is too large "+str(bl_size / 1024)+"kB" end
+
+    print("OTA: Flashing bootloader")
+    # from now on there is no turning back, any failure means a bricked device
+    import flash
+    # read current value for bytes 2/3
+    var cur_config = flash.read(addr, 4)
+
+    flash.erase(addr, self._addr_high - addr)   # erase the bootloader
+    var buf = bl.readbytes(0x1000)              # read by chunks of 4kb
+    # put back signature
+    buf[2] = cur_config[2]
+    buf[3] = cur_config[3]
+    while size(buf) > 0
+      flash.write(addr, buf, true)        # set flag to no-erase since we already erased it
+      addr += size(buf)
+      buf = bl.readbytes(0x1000)            # read next chunk
+    end
+    bl.close()
+    print("OTA: Booloader flashed, please restart")
+
+  end
+end
+
+return bootloader
+
+#-
+
+### FLASH
+import bootloader
+bootloader().flash('https://raw.githubusercontent.com/espressif/arduino-esp32/master/tools/sdk/esp32/bin/bootloader_dio_40m.bin')
+
+#bootloader().flash('https://raw.githubusercontent.com/espressif/arduino-esp32/master/tools/sdk/esp32/bin/bootloader_dout_40m.bin')
+
+#### debug only
+import string
+bl = bootloader()
+print(string.format("0x%04X", bl.get_bootloader_address()))
+
+-#
\ No newline at end of file