A well tool can include multiple electrical devices and multiple electronic circuits which control operation of the respective electrical devices, each electronic circuit including a respective isolation circuit, wherein each of the isolation circuits isolates a corresponding one of the electronic circuits from a respective one of the electrical devices in response to a predetermined condition. A method of operating a well tool can include providing multiple electronic circuits for operation of respective multiple electrical devices of the well tool, disconnecting one electronic circuit from its respective electrical device in the well, and connecting another electronic circuit to the electrical device in the well. Another method of operating a well tool can include providing multiple electronic circuits for operation of respective multiple electrical devices of the well tool, disconnecting one electronic circuit from its respective electrical device in the well, and connecting the electronic circuit to another electrical device.