Bootloader programming issue The flash is not erased

[ting²]

Hi everyone, I am using the nRF51822, I have an issue of programming the bootloader. It is said that the flash is not erased. But I just did an erase all before programming. Is there anyone who encountered the same issue? Thanks!

[Keton]

It appears that my board layout may be a problem. We've planned on using p0.21 as normal gpio and it turns out that cutting the trace leading to this pin allows us to program the nRF52. Please correct me if I'm wrong but default state of the chip after erase should be that reset on pin is disabled?