Secure triple-DES encryption using a 112-bit key derived from the password
What? Triple-DES is secure? Do you know that NIST has deprecated 3DES in 2017?
Even looking at the bit length naively, anything below 128-bits hardly can be considered secure.
or whether you will need to implement these yourself (ie. ECDSA, AES256, RIPEMD160 etc)
And that's how you lost your Bitcoin, either by wrong implementation which leads to invalid public key/address or weak entropy source for private key generation.
You can program PalmOS at least in C , C++ and assembler, but I guess that any programming language is able to be used given enough work.
Also, libraries written in C and C++ already exist, so porting them to the Palm OS won't be a huge problem. There is MathLib.prc shared Palm OS math library ,which itself is based on the Sun Microsystems' libm:
https://github.com/fidian/MathLibMaybe we can take the existing code for generating secure cold wallets, including appropriate libraries and port them to Palm OS. The only hard work that remains is programming an user interface to allow usage of the program and additional security features such as locking access to the rest of the OS without explicit user's consent.
How about support for older processor architecture? For example, Palm TX uses Intel XScale PXA 270, where Intel XScale itself uses ARMv5.
At very least, you need to find compiler which support ARMv5 and manually convert assembly code.