This needs a tweak from someone that actually knows Python. I think it needs some formatting ant to be put behind a command line flag, but there may be inspiration in here. (Or it may be garbage...)

https://pastebin.com/PV9QGLW4

I was revisiting this for the BL706 ('it's the same, they said...') and came across an error that I suspect is just another incompatibility across python versions. With

python3 --version
Python 3.9.5

an attempt to run python3 ./bltool.py -L -p /dev/cu.usbmodem0000000200001 -w 0x23000000 /tmp/lvgl_main.bin

will result in a a parse error for 0x230000000 as base 10. It looks like

diff --git a/bltool.py b/bltool.py
index 07d403c..5409a5e 100644
--- a/bltool.py
+++ b/bltool.py
@@ -288,7 +288,7 @@ def main():
eflash.eraseFlash()

     if args.write:

•        address = int(args.write[0])
  

•        address = int(args.write[0], 0)
         filename = args.write[1]
         print("Writing file {} to address 0x{:08x}...".format(filename, address))
         with open(filename, "rb") as f:
  

is the style of change needed. I'll leave it to you to figure out how to do that across Python versions that you care about.

Thanx!