ESP-07 AT command download 4,5Mb files

[Woutnme]

Hi people, my english not the best i hope can understand my doubts.
I i have a SoC connected by uart to ESP-07 Module (ESP8266) im fighting with the module to try download this size of file,
The biggest download can archive 95% of this file one time.
Our SoC run a lua runtime like a RTOS, have access to callback of byte from uart and send bytes.
Maybe some body have a good flow program to archive this, actually im ussing range function for write blocks.
But this are very slow now
Thanks