update docs for isp

docs/memory_write_error,_use_debug_for_more_info.md

@@ -7,7 +7,7 @@ In rare circumstances, your keyboard/device can become unwritable, and `dfu-prog
     [ X  ERROR
     Memory write error, use debug for more info.
 
-Currently the only way to solve this is to [reprogram the chip via ISP](https://www.reddit.com/r/olkb/comments/4rjzen/flashing_error_on_mac_os_x/d52rj8o/). This requires another device to be hooked up to a couple of exposed pins on the PCB. There is a guide on how to do this [here](https://learn.sparkfun.com/tutorials/installing-an-arduino-bootloader), and [this is where things are on the Planck PCB](http://imgur.com/lvbxbHt).
+Currently the only way to solve this is to [reprogram the chip via ISP](https://www.reddit.com/r/olkb/comments/4rjzen/flashing_error_on_mac_os_x/d52rj8o/). This requires another device to be hooked up to a couple of exposed pins on the PCB. __[We now have a guide on ISP flashing](isp_flashing_guide.md)__ and [this is where things are on the Planck PCB](http://imgur.com/lvbxbHt).
 
 An example command to flash the board once things are hooked up is: