Hello,

What is a good USB wifi adaptor - preferably dual band although not 100% required that will work out of the box with recent Linux kernels on Raspberry Pi 2?

I currently have an adaptor based on the RTL8188CUS, but ever since upgrading from Debian Jessie (not Raspbian) to Debian Stretch, I get high packet loss. Especially ARP packets - which are somewhat important. Curiously this means IPv6 is more reliable than IPv4, although even IPv6 was its ups and downs. It is possible to access the box via IPv6 or from IPV4 that still has the MAC address cached while IPv4 ping requests fail from another box (I think this rules out wifi signal issues).

Doing Google research I found that: (a) I should disable power management mode (I have), and (b) use an alternate kernel driver. However, for (b) I am still trying to find the kernel headers, which are apparently installed by default by my imaging tool https://github.com/drtyhlpr/rpi23-gen-image, but not correctly referenced by the symlinks under /lib/modules/4.9.33-v7+/ 

https://ubuntuforums.org/showthread.php?t=2259143

https://github.com/pvaret/rtl8192cu-fixes

So wondering if picking another wifi adapter might be a better choice?