I am experiencing problems when updating the firmware on my XBee PRO which has XBP24-ZB installed. The module is installed on an original Arduino Wireless SD shield sitting on an Arduino Uno board with the processor chip removed. This is the alternative to using the Sparkfun XBee Explorer USB adapter, following advice of Jeremy Blum, the author of the book Exploring Arduino. The problem occurs in particular when I change the XBee from AT to API mode. It stops during the process and wants me to reset the module. After a second attempt it reports that there is no bootloader. With the XBee recovery option I can eventually get the module to accept the changeover but it is an erratic procedure. Any advice to get a more stable updating process?