Thank you for notifying.
We will test and get back to you.
I meet the same problem with SDK 1.3.4.
I read back the flash content, and compare with the original img. And I find that some byte in the end of the page is not correct. It seems the erase is work, but the write is not finished.
Refer to the picture, left is original img, the right is read back from SPI flash.
BTW, I am using SPI Reg mode to perform flash write and read.