There's basically zero chance 100Ω resistors are contributing to your issues on a protocol that is host-clocked and can operate in the single kilobaud range. L

There's basically zero chance 100Ω resistors are contributing to your issues on a protocol that is host-clocked and can operate in the single kilobaud range. Lower speed or try one of the other fifty debug firmware projects. https://github.com/raspberrypi/debugprobe https://github.com/raspberrypi/debugprobe https://github.com/bugadani/rusty-probe-embassy https://github.com/bugadani/rusty-probe-embassy https://github.com/probe-rs/rusty-probe https://github.com/probe-rs/rusty-probe https://github.com/ciniml/rust-dap https://github.com/ciniml/rust-dap https://github.com/ccattuto/rp2040-dap-probe https://github.com/ccattuto/rp2040-dap-probe Not all firmware implements all modes or the CMSIS-DAP spec correctly (most don't implement JTAG, either.)