Writing a little tool to peek and poke values to RAM. Here's my little end to end test ensuring it actually works :D
Edit: I'm reading and writing RAM to an nRF52, a 64MHz microcontroller with USB and 256KiB of RAM. The other 32KiB are running the application.
$ cat hound-of-the-baskervilles.txt | head -c 229376 > hound.bin
$ time target/release/stage0-cli peek -a 0x20000000 -l 229376 -f boop.bin
target/release/stage0-cli peek -a 0x20000000 -l 229376 -f boop.bin 0.02s user 0.06s system 8% cpu 0.891 total
$ cat boop.bin | head -c 128 | xxd
00000000: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000010: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000020: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000030: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000040: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000050: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000060: ffff ffff ffff ffff ffff ffff ffff ffff ................
00000070: ffff ffff ffff ffff ffff ffff ffff ffff ................
$ time target/release/stage0-cli poke -a 0x20000000 -f hound.bin
len: 229376
target/release/stage0-cli poke -a 0x20000000 -f hound.bin 0.04s user 0.04s system 8% cpu 0.940 total
$ time target/release/stage0-cli peek -a 0x20000000 -l 229376 -f boop.bin
target/release/stage0-cli peek -a 0x20000000 -l 229376 -f boop.bin 0.02s user 0.06s system 9% cpu 0.866 total
$ cat boop.bin | head -c 128 | xxd
00000000: 693b 3c4d 4253 263e 0a0a 0a0a 496e 0a0a i;<MBS&>....In..
00000010: 0a0a 484f 554e 440a 0a0a 0a4f 4620 5448 ..HOUND....OF TH
00000020: 450a 4241 354b 4552 7969 4c4c 4553 0a0a E.BA5KERyiLLES..
00000030: 0a0a 0a41 2e47 2e4a 2e0a 0a0a 0a43 4f4e ...A.G.J.....CON
00000040: 414e 2044 4f59 4545 0a0a 0a0a 7269 0a0a AN DOYEE....ri..
00000050: 0a0a 0a0a 0a0a 556e 6976 6572 7369 7479 ......University
00000060: 206f 6620 4361 6c69 666f 726e 6961 20e2 of California .
00000070: 80a2 2042 6572 6b65 6c65 790a 4769 6674 .. Berkeley.Gift
$ sha256sum *.bin
bad0e0a674772058f5d13400187367579244fcd0e9f0b34c8f6a2629ef74236c boop.bin
bad0e0a674772058f5d13400187367579244fcd0e9f0b34c8f6a2629ef74236c hound.binsyntax highlighting by codehost
I have a demo building an application, which you can "poke" into memory with the bootloader, then command the bootloader to jump to.
Check it out here: