This has been reverse engineered from the toolchain only and has not been tested on hardware.
The c.lbu, c.lhu, c.sb, and c.sh opcodes replace some standard opcodes (that the QingKe cores do not implement, as the replaced opcodes require the D extension), and they also appear to be compatible with "Huawei" extensions mentioned here.
The c.lbusp, c.lhusp, c.sbsp, and c.shsp opcodes exist in a "reserved" opcode block.
001 uimm[0] uimm[4:3] rs1` uimm[2:1] rd` 00 c.lbu (replacing c.fld)
100 00 uimm[3:0] 00 rd` 00 c.lbusp
100 00 uimm[3:1] uimm[4] 01 rd` 00 c.lhusp
100 00 uimm[3:0] 10 rs2` 00 c.sbsp
100 00 uimm[3:1] uimm[4] 11 rs2` 00 c.shsp
101 uimm[0] uimm[4:3] rs1` uimm[2:1] rs2` 00 c.sb (replacing c.fsd)
001 uimm[5:3] rs1` uimm[2:1] rd` 10 c.lhu (replacing c.fldsp)
101 uimm[5:3] rs1` uimm[2:1] rs2` 10 c.sh (replacing c.fsdsp)