Currently validating checksums requires lots of knowledge on the part of the caller. We should expose optional checksum validation in our existing validation functions e.g. IPv4.IsValid.

header.UDP and header.TCP don't currently have these functions; we should add them.

If I rattle on the keyboard I get ControlLeft coming up regularly, even though I am far from the control keys. Upgrading pc_keyboard to 0.5.0 seems to fix it.

With Tock running on this board with virtual_uart sitting on top of USB, the Nano 33 BLE is a reasonably promising board to be a standard, well supported Tock board. Additionally, if the board turns out to not be great, the infrastructure which would make the Nano 33 BLE work well would apply to any other board that has the nRF52840 + USB combination.

• Make the bootloader and tockloader ex

When root filesystem fails and drops to initramfs, it is impossible to mount fat32 boot partition to correct and error
the error message is "IO charset ascii not found".
I believe nls_ascii should be built-in to solve this problem