[IC] replacement BLE module for Keychron keyboards

[mind_prepared]

I've been gettings lots of enquiries from people with Keychron keyboards regarding compatibility with the HID proxy dongle I sell. Well, after going through a pile of wireless keyboards, including Keychron's, to investigate the issue, I learnt that most Keychron keyboards, quite a few budget BT keyboards, in fact, regardless of branding, are based on Broadcom's ancient BCM20730 chipset (ARM core running HID firmware + BT transceiver). This chipset has been around for a while and survived two takeovers (Broadcom->Cypress->Infineon). Chip packages are currently mostly marked with CYW20730, but BCM20730 can also still be found in many older devices.

Although the BT stack has received numerous updates since the chipset was released in January 2011, the hardware seems to be incapable of implementing the BT Low Energy protocol. I was considering making a replacement BT LE module for Keychron boards (which would require desoldering the original module and soldering the replacement module to the keyboard PCB). This would free people from the limitations of BT Classic (BR/EDR) and boost battery life. It seemed to me that there were quite a lot of people with Keychron keyboards that might be interested in a little upgrade. Then again, perhaps it's a silly idea, better take a poll first. =^)

I'll shortly update this post with more information and technical background if enough people will take kindly to it.